Merge branch 'dev' into rp2040-upload-improvements

CODEOWNERS

@@ -55,6 +55,7 @@ esphome/components/audio/* @kahrendt
 esphome/components/audio_adc/* @kbx81
 esphome/components/audio_dac/* @kbx81
 esphome/components/audio_file/* @kahrendt
+esphome/components/audio_file/media_source/* @kahrendt
 esphome/components/axs15231/* @clydebarrow
 esphome/components/b_parasite/* @rbaron
 esphome/components/ballu/* @bazuchan

esphome/components/api/api_connection.h

@@ -354,7 +354,8 @@ class APIConnection final : public APIServerConnectionBase {
 
     // Set common EntityBase properties
 #ifdef USE_ENTITY_ICON
-    msg.icon = entity->get_icon_ref();
+    char icon_buf[MAX_ICON_LENGTH];
+    msg.icon = StringRef(entity->get_icon_to(icon_buf));
 #endif
     msg.disabled_by_default = entity->is_disabled_by_default();
     msg.entity_category = static_cast<enums::EntityCategory>(entity->get_entity_category());

esphome/components/api/api_frame_helper_noise.cpp

@@ -269,7 +269,7 @@ APIError APINoiseFrameHelper::state_action_() {
   }
   if (state_ == State::SERVER_HELLO) {
     // send server hello
-    const std::string &name = App.get_name();
+    const auto &name = App.get_name();
     char mac[MAC_ADDRESS_BUFFER_SIZE];
     get_mac_address_into_buffer(mac);
 

esphome/components/audio_file/media_source/__init__.py

@@ -0,0 +1,38 @@
+import esphome.codegen as cg
+from esphome.components import media_source, psram
+import esphome.config_validation as cv
+from esphome.const import CONF_ID, CONF_TASK_STACK_IN_PSRAM
+from esphome.types import ConfigType
+
+CODEOWNERS = ["@kahrendt"]
+AUTO_LOAD = ["audio"]
+DEPENDENCIES = ["audio_file"]
+
+audio_file_ns = cg.esphome_ns.namespace("audio_file")
+AudioFileMediaSource = audio_file_ns.class_(
+    "AudioFileMediaSource", cg.Component, media_source.MediaSource
+)
+
+CONFIG_SCHEMA = cv.All(
+    media_source.media_source_schema(
+        AudioFileMediaSource,
+    )
+    .extend(
+        {
+            cv.Optional(CONF_TASK_STACK_IN_PSRAM): cv.All(
+                cv.boolean, cv.requires_component(psram.DOMAIN)
+            ),
+        }
+    )
+    .extend(cv.COMPONENT_SCHEMA),
+    cv.only_on_esp32,
+)
+
+
+async def to_code(config: ConfigType) -> None:
+    var = cg.new_Pvariable(config[CONF_ID])
+    await cg.register_component(var, config)
+    await media_source.register_media_source(var, config)
+
+    if CONF_TASK_STACK_IN_PSRAM in config:
+        cg.add(var.set_task_stack_in_psram(config[CONF_TASK_STACK_IN_PSRAM]))

esphome/components/audio_file/media_source/audio_file_media_source.cpp

@@ -0,0 +1,283 @@
+#include "audio_file_media_source.h"
+
+#ifdef USE_ESP32
+
+#include "esphome/components/audio/audio_decoder.h"
+
+#include <cstring>
+
+namespace esphome::audio_file {
+
+namespace {  // anonymous namespace for internal linkage
+struct AudioSinkAdapter : public audio::AudioSinkCallback {
+  media_source::MediaSource *source;
+  audio::AudioStreamInfo stream_info;
+
+  size_t audio_sink_write(uint8_t *data, size_t length, TickType_t ticks_to_wait) override {
+    return this->source->write_output(data, length, pdTICKS_TO_MS(ticks_to_wait), this->stream_info);
+  }
+};
+}  // namespace
+
+#if defined(USE_AUDIO_OPUS_SUPPORT)
+static constexpr uint32_t DECODE_TASK_STACK_SIZE = 5 * 1024;
+#else
+static constexpr uint32_t DECODE_TASK_STACK_SIZE = 3 * 1024;
+#endif
+
+static const char *const TAG = "audio_file_media_source";
+
+enum EventGroupBits : uint32_t {
+  // Requests to start playback (set by play_uri, handled by loop)
+  REQUEST_START = (1 << 0),
+  // Commands from main loop to decode task
+  COMMAND_STOP = (1 << 1),
+  COMMAND_PAUSE = (1 << 2),
+  // Decode task lifecycle signals (one-shot, cleared by loop)
+  TASK_STARTING = (1 << 7),
+  TASK_RUNNING = (1 << 8),
+  TASK_STOPPING = (1 << 9),
+  TASK_STOPPED = (1 << 10),
+  TASK_ERROR = (1 << 11),
+  // Decode task state (level-triggered, set/cleared by decode task)
+  TASK_PAUSED = (1 << 12),
+  ALL_BITS = 0x00FFFFFF,  // All valid FreeRTOS event group bits
+};
+
+void AudioFileMediaSource::dump_config() {
+  ESP_LOGCONFIG(TAG, "Audio File Media Source:");
+  ESP_LOGCONFIG(TAG, "  Task Stack in PSRAM: %s", this->task_stack_in_psram_ ? "Yes" : "No");
+}
+
+void AudioFileMediaSource::setup() {
+  this->disable_loop();
+
+  this->event_group_ = xEventGroupCreate();
+  if (this->event_group_ == nullptr) {
+    ESP_LOGE(TAG, "Failed to create event group");
+    this->mark_failed();
+    return;
+  }
+}
+
+void AudioFileMediaSource::loop() {
+  EventBits_t event_bits = xEventGroupGetBits(this->event_group_);
+
+  if (event_bits & REQUEST_START) {
+    xEventGroupClearBits(this->event_group_, REQUEST_START);
+    this->decoding_state_ = AudioFileDecodingState::START_TASK;
+  }
+
+  switch (this->decoding_state_) {
+    case AudioFileDecodingState::START_TASK: {
+      if (!this->decode_task_.is_created()) {
+        xEventGroupClearBits(this->event_group_, ALL_BITS);
+        if (!this->decode_task_.create(decode_task, "AudioFileDec", DECODE_TASK_STACK_SIZE, this, 1,
+                                       this->task_stack_in_psram_)) {
+          ESP_LOGE(TAG, "Failed to create task");
+          this->status_momentary_error("task_create", 1000);
+          this->set_state_(media_source::MediaSourceState::ERROR);
+          this->decoding_state_ = AudioFileDecodingState::IDLE;
+          return;
+        }
+      }
+      this->decoding_state_ = AudioFileDecodingState::DECODING;
+      break;
+    }
+    case AudioFileDecodingState::DECODING: {
+      if (event_bits & TASK_STARTING) {
+        ESP_LOGD(TAG, "Starting");
+        xEventGroupClearBits(this->event_group_, TASK_STARTING);
+      }
+
+      if (event_bits & TASK_RUNNING) {
+        ESP_LOGV(TAG, "Started");
+        xEventGroupClearBits(this->event_group_, TASK_RUNNING);
+        this->set_state_(media_source::MediaSourceState::PLAYING);
+      }
+
+      if ((event_bits & TASK_PAUSED) && this->get_state() != media_source::MediaSourceState::PAUSED) {
+        this->set_state_(media_source::MediaSourceState::PAUSED);
+      } else if (!(event_bits & TASK_PAUSED) && this->get_state() == media_source::MediaSourceState::PAUSED) {
+        this->set_state_(media_source::MediaSourceState::PLAYING);
+      }
+
+      if (event_bits & TASK_STOPPING) {
+        ESP_LOGV(TAG, "Stopping");
+        xEventGroupClearBits(this->event_group_, TASK_STOPPING);
+      }
+
+      if (event_bits & TASK_ERROR) {
+        // Report error so the orchestrator knows playback failed; task will have already logged the specific error
+        this->set_state_(media_source::MediaSourceState::ERROR);
+      }
+
+      if (event_bits & TASK_STOPPED) {
+        ESP_LOGD(TAG, "Stopped");
+        xEventGroupClearBits(this->event_group_, ALL_BITS);
+
+        this->decode_task_.deallocate();
+        this->set_state_(media_source::MediaSourceState::IDLE);
+        this->decoding_state_ = AudioFileDecodingState::IDLE;
+      }
+      break;
+    }
+    case AudioFileDecodingState::IDLE: {
+      if (this->get_state() == media_source::MediaSourceState::ERROR && !this->status_has_error()) {
+        this->set_state_(media_source::MediaSourceState::IDLE);
+      }
+      break;
+    }
+  }
+
+  if ((this->decoding_state_ == AudioFileDecodingState::IDLE) &&
+      (this->get_state() == media_source::MediaSourceState::IDLE)) {
+    this->disable_loop();
+  }
+}
+
+// Called from the orchestrator's main loop, so no synchronization needed with loop()
+bool AudioFileMediaSource::play_uri(const std::string &uri) {
+  if (!this->is_ready() || this->is_failed() || this->status_has_error() || !this->has_listener() ||
+      xEventGroupGetBits(this->event_group_) & REQUEST_START) {
+    return false;
+  }
+
+  // Check if source is already playing
+  if (this->get_state() != media_source::MediaSourceState::IDLE) {
+    ESP_LOGE(TAG, "Cannot play '%s': source is busy", uri.c_str());
+    return false;
+  }
+
+  // Validate URI starts with "audio-file://"
+  if (!uri.starts_with("audio-file://")) {
+    ESP_LOGE(TAG, "Invalid URI: '%s'", uri.c_str());
+    return false;
+  }
+
+  // Strip "audio-file://" prefix and find the file
+  const char *file_id = uri.c_str() + 13;  // "audio-file://" is 13 characters
+
+  for (const auto &named_file : get_named_audio_files()) {
+    if (strcmp(named_file.file_id, file_id) == 0) {
+      this->current_file_ = named_file.file;
+      xEventGroupSetBits(this->event_group_, EventGroupBits::REQUEST_START);
+      this->enable_loop();
+      return true;
+    }
+  }
+
+  ESP_LOGE(TAG, "Unknown file: '%s'", file_id);
+  return false;
+}
+
+// Called from the orchestrator's main loop, so no synchronization needed with loop()
+void AudioFileMediaSource::handle_command(media_source::MediaSourceCommand command) {
+  if (this->decoding_state_ != AudioFileDecodingState::DECODING) {
+    return;
+  }
+
+  switch (command) {
+    case media_source::MediaSourceCommand::STOP:
+      xEventGroupSetBits(this->event_group_, EventGroupBits::COMMAND_STOP);
+      break;
+    case media_source::MediaSourceCommand::PAUSE:
+      xEventGroupSetBits(this->event_group_, EventGroupBits::COMMAND_PAUSE);
+      break;
+    case media_source::MediaSourceCommand::PLAY:
+      xEventGroupClearBits(this->event_group_, EventGroupBits::COMMAND_PAUSE);
+      break;
+    default:
+      break;
+  }
+}
+
+void AudioFileMediaSource::decode_task(void *params) {
+  AudioFileMediaSource *this_source = static_cast<AudioFileMediaSource *>(params);
+
+  do {  // do-while(false) ensures RAII objects are destroyed on all exit paths via break
+
+    xEventGroupSetBits(this_source->event_group_, EventGroupBits::TASK_STARTING);
+
+    // 0 bytes for input transfer buffer makes it an inplace buffer
+    std::unique_ptr<audio::AudioDecoder> decoder = make_unique<audio::AudioDecoder>(0, 4096);
+
+    esp_err_t err = decoder->start(this_source->current_file_->file_type);
+    if (err != ESP_OK) {
+      ESP_LOGE(TAG, "Failed to start decoder: %s", esp_err_to_name(err));
+      xEventGroupSetBits(this_source->event_group_, EventGroupBits::TASK_ERROR | EventGroupBits::TASK_STOPPING);
+      break;
+    }
+
+    // Add the file as a const data source
+    decoder->add_source(this_source->current_file_->data, this_source->current_file_->length);
+
+    xEventGroupSetBits(this_source->event_group_, EventGroupBits::TASK_RUNNING);
+
+    AudioSinkAdapter audio_sink;
+    bool has_stream_info = false;
+
+    while (true) {
+      EventBits_t event_bits = xEventGroupGetBits(this_source->event_group_);
+
+      if (event_bits & EventGroupBits::COMMAND_STOP) {
+        break;
+      }
+
+      bool paused = event_bits & EventGroupBits::COMMAND_PAUSE;
+      decoder->set_pause_output_state(paused);
+      if (paused) {
+        xEventGroupSetBits(this_source->event_group_, EventGroupBits::TASK_PAUSED);
+        vTaskDelay(pdMS_TO_TICKS(20));
+      } else {
+        xEventGroupClearBits(this_source->event_group_, EventGroupBits::TASK_PAUSED);
+      }
+
+      // Will stop gracefully once finished with the current file
+      audio::AudioDecoderState decoder_state = decoder->decode(true);
+
+      if (decoder_state == audio::AudioDecoderState::FINISHED) {
+        break;
+      } else if (decoder_state == audio::AudioDecoderState::FAILED) {
+        ESP_LOGE(TAG, "Decoder failed");
+        xEventGroupSetBits(this_source->event_group_, EventGroupBits::TASK_ERROR);
+        break;
+      }
+
+      if (!has_stream_info && decoder->get_audio_stream_info().has_value()) {
+        has_stream_info = true;
+
+        audio::AudioStreamInfo stream_info = decoder->get_audio_stream_info().value();
+
+        ESP_LOGD(TAG, "Bits per sample: %d, Channels: %d, Sample rate: %d", stream_info.get_bits_per_sample(),
+                 stream_info.get_channels(), stream_info.get_sample_rate());
+
+        if (stream_info.get_bits_per_sample() != 16 || stream_info.get_channels() > 2) {
+          ESP_LOGE(TAG, "Incompatible audio stream. Only 16 bits per sample and 1 or 2 channels are supported");
+          xEventGroupSetBits(this_source->event_group_, EventGroupBits::TASK_ERROR);
+          break;
+        }
+
+        audio_sink.source = this_source;
+        audio_sink.stream_info = stream_info;
+        esp_err_t err = decoder->add_sink(&audio_sink);
+        if (err != ESP_OK) {
+          ESP_LOGE(TAG, "Failed to add sink: %s", esp_err_to_name(err));
+          xEventGroupSetBits(this_source->event_group_, EventGroupBits::TASK_ERROR);
+          break;
+        }
+      }
+    }
+
+    xEventGroupSetBits(this_source->event_group_, EventGroupBits::TASK_STOPPING);
+  } while (false);
+
+  // All RAII objects from the do-while block (decoder, audio_sink, etc.) are now destroyed.
+
+  xEventGroupSetBits(this_source->event_group_, EventGroupBits::TASK_STOPPED);
+  vTaskSuspend(nullptr);  // Suspend this task indefinitely until the loop method deletes it
+}
+
+}  // namespace esphome::audio_file
+
+#endif  // USE_ESP32

esphome/components/audio_file/media_source/audio_file_media_source.h

@@ -0,0 +1,50 @@
+#pragma once
+
+#include "esphome/core/defines.h"
+
+#ifdef USE_ESP32
+
+#include "esphome/components/audio/audio.h"
+#include "esphome/components/audio_file/audio_file.h"
+#include "esphome/components/media_source/media_source.h"
+#include "esphome/core/component.h"
+#include "esphome/core/static_task.h"
+
+#include <freertos/FreeRTOS.h>
+#include <freertos/event_groups.h>
+
+namespace esphome::audio_file {
+
+enum class AudioFileDecodingState : uint8_t {
+  START_TASK,
+  DECODING,
+  IDLE,
+};
+
+class AudioFileMediaSource : public Component, public media_source::MediaSource {
+ public:
+  void setup() override;
+  void loop() override;
+  void dump_config() override;
+
+  // MediaSource interface implementation
+  bool play_uri(const std::string &uri) override;
+  void handle_command(media_source::MediaSourceCommand command) override;
+  bool can_handle(const std::string &uri) const override { return uri.starts_with("audio-file://"); }
+
+  void set_task_stack_in_psram(bool task_stack_in_psram) { this->task_stack_in_psram_ = task_stack_in_psram; }
+
+ protected:
+  static void decode_task(void *params);
+
+  audio::AudioFile *current_file_{nullptr};
+  AudioFileDecodingState decoding_state_{AudioFileDecodingState::IDLE};
+  EventGroupHandle_t event_group_{nullptr};
+  StaticTask decode_task_;
+
+  bool task_stack_in_psram_{false};
+};
+
+}  // namespace esphome::audio_file
+
+#endif  // USE_ESP32

esphome/components/ble_nus/__init__.py

@@ -1,29 +1,64 @@
 import esphome.codegen as cg
 from esphome.components.logger import request_log_listener
+from esphome.components.uart import (
+    UARTComponent,
+    debug_to_code,
+    maybe_empty_debug,
+    uart_ns,
+)
 from esphome.components.zephyr import zephyr_add_prj_conf
 import esphome.config_validation as cv
-from esphome.const import CONF_ID, CONF_LOGS, CONF_TYPE
+from esphome.const import (
+    CONF_DEBUG,
+    CONF_ID,
+    CONF_LOGS,
+    CONF_RX_BUFFER_SIZE,
+    CONF_TX_BUFFER_SIZE,
+    CONF_TYPE,
+)
+from esphome.types import ConfigType
 
-AUTO_LOAD = ["zephyr_ble_server"]
+AUTO_LOAD = ["zephyr_ble_server", "uart"]
 CODEOWNERS = ["@tomaszduda23"]
 
 ble_nus_ns = cg.esphome_ns.namespace("ble_nus")
-BLENUS = ble_nus_ns.class_("BLENUS", cg.Component)
+BLENUS = ble_nus_ns.class_("BLENUS", cg.Component, UARTComponent)
+
+CONF_UART = "uart"
+
+
+def validate_rx_buffer(config: ConfigType) -> ConfigType:
+    config = config.copy()
+    if config[CONF_TYPE] == CONF_LOGS:
+        if CONF_RX_BUFFER_SIZE in config:
+            raise cv.Invalid("logs does not support rx_buffer_size")
+    elif CONF_RX_BUFFER_SIZE not in config:
+        config[CONF_RX_BUFFER_SIZE] = 512
+    return config
+
 
 CONFIG_SCHEMA = cv.All(
     cv.Schema(
         {
             cv.GenerateID(): cv.declare_id(BLENUS),
             cv.Optional(CONF_TYPE, default=CONF_LOGS): cv.one_of(
-                *[CONF_LOGS], lower=True
+                *[CONF_LOGS, CONF_UART], lower=True
             ),
+            cv.Optional(CONF_TX_BUFFER_SIZE, default=512): cv.All(
+                cv.validate_bytes, cv.int_range(min=160, max=8192)
+            ),
+            cv.Optional(CONF_RX_BUFFER_SIZE): cv.All(
+                cv.validate_bytes, cv.int_range(min=160, max=8192)
+            ),
+            cv.Optional(CONF_DEBUG): maybe_empty_debug,
         }
     ).extend(cv.COMPONENT_SCHEMA),
     cv.only_with_framework("zephyr"),
+    validate_rx_buffer,
 )
 
 
-async def to_code(config):
+async def to_code(config: ConfigType) -> None:
     var = cg.new_Pvariable(config[CONF_ID])
     zephyr_add_prj_conf("BT_NUS", True)
     expose_log = config[CONF_TYPE] == CONF_LOGS
@@ -31,3 +66,11 @@ async def to_code(config):
     if expose_log:
         request_log_listener()  # Request a log listener slot for BLE NUS log streaming
     await cg.register_component(var, config)
+    cg.add_define("ESPHOME_BLE_NUS_TX_RING_BUFFER_SIZE", config[CONF_TX_BUFFER_SIZE])
+    if CONF_RX_BUFFER_SIZE in config:
+        cg.add_define(
+            "ESPHOME_BLE_NUS_RX_RING_BUFFER_SIZE", config[CONF_RX_BUFFER_SIZE]
+        )
+    if CONF_DEBUG in config:
+        cg.add_global(uart_ns.using)
+        await debug_to_code(config[CONF_DEBUG], var)

esphome/components/ble_nus/ble_nus.cpp

@@ -11,25 +11,111 @@
 
 namespace esphome::ble_nus {
 
-constexpr size_t BLE_TX_BUF_SIZE = 2048;
-
 // NOLINTBEGIN(cppcoreguidelines-avoid-non-const-global-variables)
 BLENUS *global_ble_nus;
-RING_BUF_DECLARE(global_ble_tx_ring_buf, BLE_TX_BUF_SIZE);
+RING_BUF_DECLARE(global_ble_tx_ring_buf, ESPHOME_BLE_NUS_TX_RING_BUFFER_SIZE);
+#ifdef ESPHOME_BLE_NUS_RX_RING_BUFFER_SIZE
+RING_BUF_DECLARE(global_ble_rx_ring_buf, ESPHOME_BLE_NUS_RX_RING_BUFFER_SIZE);
+#endif
 // NOLINTEND(cppcoreguidelines-avoid-non-const-global-variables)
 
 static const char *const TAG = "ble_nus";
 
-size_t BLENUS::write_array(const uint8_t *data, size_t len) {
+void BLENUS::write_array(const uint8_t *data, size_t len) {
   if (atomic_get(&this->tx_status_) == TX_DISABLED) {
-    return 0;
+    return;
+  }
+  auto sent = ring_buf_put(&global_ble_tx_ring_buf, data, len);
+  if (sent < len) {
+    ESP_LOGE(TAG, "TX dropping %u bytes", len - sent);
+    return;
+  }
+#ifdef USE_UART_DEBUGGER
+  for (size_t i = 0; i < len; i++) {
+    this->debug_callback_.call(uart::UART_DIRECTION_TX, data[i]);
+  }
+#endif
+}
+
+bool BLENUS::peek_byte(uint8_t *data) {
+#ifdef ESPHOME_BLE_NUS_RX_RING_BUFFER_SIZE
+  if (this->has_peek_) {
+    *data = this->peek_buffer_;
+    return true;
+  }
+
+  if (this->read_byte(&this->peek_buffer_)) {
+    *data = this->peek_buffer_;
+    this->has_peek_ = true;
+    return true;
+  }
+
+  return false;
+#else
+  return false;
+#endif
+}
+
+bool BLENUS::read_array(uint8_t *data, size_t len) {
+#ifdef ESPHOME_BLE_NUS_RX_RING_BUFFER_SIZE
+  if (len == 0) {
+    return true;
+  }
+  if (this->available() < len) {
+    return false;
+  }
+
+  // First, use the peek buffer if available
+  if (this->has_peek_) {
+    data[0] = this->peek_buffer_;
+    this->has_peek_ = false;
+    data++;
+    if (--len == 0) {  // Decrement len first, then check it...
+      return true;     // No more to read
+    }
+  }
+
+  if (ring_buf_get(&global_ble_rx_ring_buf, data, len) != len) {
+    ESP_LOGE(TAG, "UART BLE unexpected size");
+    return false;
+  }
+#ifdef USE_UART_DEBUGGER
+  for (size_t i = 0; i < len; i++) {
+    this->debug_callback_.call(uart::UART_DIRECTION_RX, data[i]);
+  }
+#endif
+  return true;
+#else
+  return false;
+#endif
+}
+
+size_t BLENUS::available() {
+#ifdef ESPHOME_BLE_NUS_RX_RING_BUFFER_SIZE
+  uint32_t size = ring_buf_size_get(&global_ble_rx_ring_buf);
+  ESP_LOGVV(TAG, "UART BLE available %u", size);
+  return size + (this->has_peek_ ? 1 : 0);
+#else
+  return 0;
+#endif
+}
+
+void BLENUS::flush() {
+  constexpr uint32_t timeout_5sec = 5000;
+  uint32_t start = millis();
+  while (atomic_get(&this->tx_status_) != TX_DISABLED && !ring_buf_is_empty(&global_ble_tx_ring_buf)) {
+    if (millis() - start > timeout_5sec) {
+      ESP_LOGW(TAG, "Flush timeout");
+      return;
+    }
+    delay(1);
   }
-  return ring_buf_put(&global_ble_tx_ring_buf, data, len);
 }
 
 void BLENUS::connected(bt_conn *conn, uint8_t err) {
   if (err == 0) {
     global_ble_nus->conn_.store(bt_conn_ref(conn));
+    global_ble_nus->connected_ = true;
   }
 }
 
@@ -38,6 +124,7 @@ void BLENUS::disconnected(bt_conn *conn, uint8_t reason) {
     bt_conn_unref(global_ble_nus->conn_.load());
     // Connection array is global static.
     // Reference can be kept even if disconnected.
+    global_ble_nus->connected_ = false;
   }
 }
 
@@ -63,12 +150,19 @@ void BLENUS::send_enabled_callback(bt_nus_send_status status) {
       break;
   }
 }
-
 void BLENUS::rx_callback(bt_conn *conn, const uint8_t *const data, uint16_t len) {
-  ESP_LOGD(TAG, "Received %d bytes.", len);
+  ESP_LOGV(TAG, "Received %d bytes.", len);
+#ifdef ESPHOME_BLE_NUS_RX_RING_BUFFER_SIZE
+  auto recv_len = ring_buf_put(&global_ble_rx_ring_buf, data, len);
+  if (recv_len < len) {
+    ESP_LOGE(TAG, "RX dropping %u bytes", len - recv_len);
+  }
+#endif
 }
-
 void BLENUS::setup() {
+#ifdef ESPHOME_BLE_NUS_RX_RING_BUFFER_SIZE
+  this->rx_buffer_size_ = ESPHOME_BLE_NUS_RX_RING_BUFFER_SIZE;
+#endif
   bt_nus_cb callbacks = {
       .received = rx_callback,
       .sent = tx_callback,
@@ -106,16 +200,17 @@ void BLENUS::on_log(uint8_t level, const char *tag, const char *message, size_t
 #endif
 
 void BLENUS::dump_config() {
-  ESP_LOGCONFIG(TAG,
-                "ble nus:\n"
-                "  log: %s",
-                YESNO(this->expose_log_));
   uint32_t mtu = 0;
   bt_conn *conn = this->conn_.load();
-  if (conn) {
+  if (conn && this->connected_) {
     mtu = bt_nus_get_mtu(conn);
   }
-  ESP_LOGCONFIG(TAG, "  MTU: %u", mtu);
+  ESP_LOGCONFIG(TAG,
+                "ble nus:\n"
+                "  log: %s\n"
+                "  connected: %s\n"
+                "  MTU: %u",
+                YESNO(this->expose_log_), YESNO(this->connected_.load()), mtu);
 }
 
 void BLENUS::loop() {

esphome/components/ble_nus/ble_nus.h

@@ -2,6 +2,7 @@
 #ifdef USE_ZEPHYR
 #include "esphome/core/defines.h"
 #include "esphome/core/component.h"
+#include "esphome/components/uart/uart_component.h"
 #ifdef USE_LOGGER
 #include "esphome/components/logger/logger.h"
 #endif
@@ -10,7 +11,7 @@
 
 namespace esphome::ble_nus {
 
-class BLENUS : public Component {
+class BLENUS : public uart::UARTComponent, public Component {
   enum TxStatus {
     TX_DISABLED,
     TX_ENABLED,
@@ -21,7 +22,12 @@ class BLENUS : public Component {
   void setup() override;
   void dump_config() override;
   void loop() override;
-  size_t write_array(const uint8_t *data, size_t len);
+  void write_array(const uint8_t *data, size_t len) override;
+  bool peek_byte(uint8_t *data) override;
+  bool read_array(uint8_t *data, size_t len) override;
+  size_t available() override;
+  void flush() override;
+  void check_logger_conflict() override {}
   void set_expose_log(bool expose_log) { this->expose_log_ = expose_log; }
 #ifdef USE_LOGGER
   void on_log(uint8_t level, const char *tag, const char *message, size_t message_len);
@@ -37,6 +43,12 @@ class BLENUS : public Component {
   std::atomic<bt_conn *> conn_ = nullptr;
   bool expose_log_ = false;
   atomic_t tx_status_ = ATOMIC_INIT(TX_DISABLED);
+  std::atomic<bool> connected_{};
+#ifdef ESPHOME_BLE_NUS_RX_RING_BUFFER_SIZE
+  // RX buffer for peek functionality
+  uint8_t peek_buffer_{0};
+  bool has_peek_{false};
+#endif
 };
 
 }  // namespace esphome::ble_nus

esphome/components/bluetooth_proxy/bluetooth_connection.cpp

@@ -415,11 +415,14 @@ bool BluetoothConnection::gattc_event_handler(esp_gattc_cb_event_t event, esp_ga
         this->proxy_->send_gatt_error(this->address_, param->read.handle, param->read.status);
         break;
       }
+      auto *api_connection = this->proxy_->get_api_connection();
+      if (api_connection == nullptr)
+        break;
       api::BluetoothGATTReadResponse resp;
       resp.address = this->address_;
       resp.handle = param->read.handle;
       resp.set_data(param->read.value, param->read.value_len);
-      this->proxy_->get_api_connection()->send_message(resp, api::BluetoothGATTReadResponse::MESSAGE_TYPE);
+      api_connection->send_message(resp, api::BluetoothGATTReadResponse::MESSAGE_TYPE);
       break;
     }
     case ESP_GATTC_WRITE_CHAR_EVT:
@@ -429,10 +432,13 @@ bool BluetoothConnection::gattc_event_handler(esp_gattc_cb_event_t event, esp_ga
         this->proxy_->send_gatt_error(this->address_, param->write.handle, param->write.status);
         break;
       }
+      auto *api_connection = this->proxy_->get_api_connection();
+      if (api_connection == nullptr)
+        break;
       api::BluetoothGATTWriteResponse resp;
       resp.address = this->address_;
       resp.handle = param->write.handle;
-      this->proxy_->get_api_connection()->send_message(resp, api::BluetoothGATTWriteResponse::MESSAGE_TYPE);
+      api_connection->send_message(resp, api::BluetoothGATTWriteResponse::MESSAGE_TYPE);
       break;
     }
     case ESP_GATTC_UNREG_FOR_NOTIFY_EVT: {
@@ -442,10 +448,13 @@ bool BluetoothConnection::gattc_event_handler(esp_gattc_cb_event_t event, esp_ga
         this->proxy_->send_gatt_error(this->address_, param->unreg_for_notify.handle, param->unreg_for_notify.status);
         break;
       }
+      auto *api_connection = this->proxy_->get_api_connection();
+      if (api_connection == nullptr)
+        break;
       api::BluetoothGATTNotifyResponse resp;
       resp.address = this->address_;
       resp.handle = param->unreg_for_notify.handle;
-      this->proxy_->get_api_connection()->send_message(resp, api::BluetoothGATTNotifyResponse::MESSAGE_TYPE);
+      api_connection->send_message(resp, api::BluetoothGATTNotifyResponse::MESSAGE_TYPE);
       break;
     }
     case ESP_GATTC_REG_FOR_NOTIFY_EVT: {
@@ -455,20 +464,26 @@ bool BluetoothConnection::gattc_event_handler(esp_gattc_cb_event_t event, esp_ga
         this->proxy_->send_gatt_error(this->address_, param->reg_for_notify.handle, param->reg_for_notify.status);
         break;
       }
+      auto *api_connection = this->proxy_->get_api_connection();
+      if (api_connection == nullptr)
+        break;
       api::BluetoothGATTNotifyResponse resp;
       resp.address = this->address_;
       resp.handle = param->reg_for_notify.handle;
-      this->proxy_->get_api_connection()->send_message(resp, api::BluetoothGATTNotifyResponse::MESSAGE_TYPE);
+      api_connection->send_message(resp, api::BluetoothGATTNotifyResponse::MESSAGE_TYPE);
       break;
     }
     case ESP_GATTC_NOTIFY_EVT: {
       ESP_LOGV(TAG, "[%d] [%s] ESP_GATTC_NOTIFY_EVT: handle=0x%2X", this->connection_index_, this->address_str_,
                param->notify.handle);
+      auto *api_connection = this->proxy_->get_api_connection();
+      if (api_connection == nullptr)
+        break;
       api::BluetoothGATTNotifyDataResponse resp;
       resp.address = this->address_;
       resp.handle = param->notify.handle;
       resp.set_data(param->notify.value, param->notify.value_len);
-      this->proxy_->get_api_connection()->send_message(resp, api::BluetoothGATTNotifyDataResponse::MESSAGE_TYPE);
+      api_connection->send_message(resp, api::BluetoothGATTNotifyDataResponse::MESSAGE_TYPE);
       break;
     }
     default:

esphome/components/bluetooth_proxy/bluetooth_proxy.cpp

@@ -420,6 +420,8 @@ void BluetoothProxy::send_gatt_error(uint64_t address, uint16_t handle, esp_err_
 }
 
 void BluetoothProxy::send_device_pairing(uint64_t address, bool paired, esp_err_t error) {
+  if (this->api_connection_ == nullptr)
+    return;
   api::BluetoothDevicePairingResponse call;
   call.address = address;
   call.paired = paired;
@@ -429,6 +431,8 @@ void BluetoothProxy::send_device_pairing(uint64_t address, bool paired, esp_err_
 }
 
 void BluetoothProxy::send_device_unpairing(uint64_t address, bool success, esp_err_t error) {
+  if (this->api_connection_ == nullptr)
+    return;
   api::BluetoothDeviceUnpairingResponse call;
   call.address = address;
   call.success = success;

esphome/components/e131/e131_addressable_light_effect.cpp

@@ -54,8 +54,10 @@ bool E131AddressableLightEffect::process_(int universe, const E131Packet &packet
 
   int32_t output_offset = (universe - first_universe_) * get_lights_per_universe();
   // limit amount of lights per universe and received
+  // packet.count is the number of DMX bytes including start code; divide by channels to get the number of lights
+  int lights_in_packet = (packet.count > 0) ? (packet.count - 1) / channels_ : 0;
   int output_end =
-      std::min(it->size(), std::min(output_offset + get_lights_per_universe(), output_offset + packet.count - 1));
+      std::min(it->size(), std::min(output_offset + get_lights_per_universe(), output_offset + lights_in_packet));
   auto *input_data = packet.values + 1;
 
   auto effect_name = get_name();

esphome/components/esp32/__init__.py

@@ -464,6 +464,8 @@ def only_on_variant(*, supported=None, unsupported=None, msg_prefix="This featur
         unsupported = [unsupported]
 
     def validator_(obj):
+        if not CORE.is_esp32:
+            raise cv.Invalid(f"{msg_prefix} is only available on ESP32")
         variant = get_esp32_variant()
         if supported is not None and variant not in supported:
             raise cv.Invalid(

esphome/components/esp32/gpio_esp32_p4.py

@@ -33,7 +33,7 @@ def esp32_p4_validate_supports(value):
     is_input = mode[CONF_INPUT]
 
     if num < 0 or num > 54:
-        raise cv.Invalid(f"Invalid pin number: {value} (must be 0-54)")
+        raise cv.Invalid(f"Invalid pin number: {num} (must be 0-54)")
     if is_input:
         # All ESP32 pins support input mode
         pass

esphome/components/esp32/gpio_esp32_s3.py

@@ -29,7 +29,7 @@ _LOGGER = logging.getLogger(__name__)
 
 def esp32_s3_validate_gpio_pin(value):
     if value < 0 or value > 48:
-        raise cv.Invalid(f"Invalid pin number: {value} (must be 0-46)")
+        raise cv.Invalid(f"Invalid pin number: {value} (must be 0-48)")
 
     if value in _ESP_32S3_SPI_PSRAM_PINS:
         raise cv.Invalid(
@@ -55,7 +55,7 @@ def esp32_s3_validate_supports(value):
     is_input = mode[CONF_INPUT]
 
     if num < 0 or num > 48:
-        raise cv.Invalid(f"Invalid pin number: {num} (must be 0-46)")
+        raise cv.Invalid(f"Invalid pin number: {num} (must be 0-48)")
     if is_input:
         # All ESP32 pins support input mode
         pass

esphome/components/esp32_ble/ble.cpp

@@ -273,7 +273,7 @@ bool ESP32BLE::ble_setup_() {
       device_name = this->name_;
     }
   } else {
-    const std::string &app_name = App.get_name();
+    const auto &app_name = App.get_name();
     size_t name_len = app_name.length();
     if (name_len > 20) {
       if (App.is_name_add_mac_suffix_enabled()) {

esphome/components/ethernet/ethernet_component.cpp

@@ -470,6 +470,7 @@ network::IPAddresses EthernetComponent::get_ip_addresses() {
   uint8_t count = 0;
   count = esp_netif_get_all_ip6(this->eth_netif_, if_ip6s);
   assert(count <= CONFIG_LWIP_IPV6_NUM_ADDRESSES);
+  assert(count < addresses.size());
   for (int i = 0; i < count; i++) {
     addresses[i + 1] = network::IPAddress(&if_ip6s[i]);
   }

esphome/components/ethernet/ethernet_component.h

@@ -115,6 +115,7 @@ class EthernetComponent : public Component {
   const char *get_eth_mac_address_pretty_into_buffer(std::span<char, MAC_ADDRESS_PRETTY_BUFFER_SIZE> buf);
   eth_duplex_t get_duplex_mode();
   eth_speed_t get_link_speed();
+  esp_eth_handle_t get_eth_handle() const { return this->eth_handle_; }
   bool powerdown();
 
 #ifdef USE_ETHERNET_IP_STATE_LISTENERS

esphome/components/hlk_fm22x/hlk_fm22x.cpp

@@ -133,24 +133,22 @@ void HlkFm22xComponent::recv_command_() {
   checksum ^= byte;
   length |= byte;
 
-  if (length > HLK_FM22X_MAX_RESPONSE_SIZE) {
-    ESP_LOGE(TAG, "Response too large: %u bytes", length);
-    // Discard exactly the remaining payload and checksum for this frame
-    for (uint16_t i = 0; i < length + 1 && this->available() > 0; ++i)
-      this->read();
-    return;
-  }
-
+  // Read up to buffer size; discard excess bytes while still computing checksum
+  // GET_ALL_FACE_IDS can return all enrolled face data (hundreds of bytes)
+  // but handlers only need the first few bytes
+  size_t to_store = std::min(static_cast<size_t>(length), HLK_FM22X_MAX_RESPONSE_SIZE);
   for (uint16_t idx = 0; idx < length; ++idx) {
     byte = this->read();
     checksum ^= byte;
-    this->recv_buf_[idx] = byte;
+    if (idx < to_store) {
+      this->recv_buf_[idx] = byte;
+    }
   }
 
 #if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE
   char hex_buf[format_hex_pretty_size(HLK_FM22X_MAX_RESPONSE_SIZE)];
   ESP_LOGV(TAG, "Recv type: 0x%.2X, data: %s", response_type,
-           format_hex_pretty_to(hex_buf, this->recv_buf_.data(), length));
+           format_hex_pretty_to(hex_buf, this->recv_buf_.data(), to_store));
 #endif
 
   byte = this->read();
@@ -160,10 +158,10 @@ void HlkFm22xComponent::recv_command_() {
   }
   switch (response_type) {
     case HlkFm22xResponseType::NOTE:
-      this->handle_note_(this->recv_buf_.data(), length);
+      this->handle_note_(this->recv_buf_.data(), to_store);
       break;
     case HlkFm22xResponseType::REPLY:
-      this->handle_reply_(this->recv_buf_.data(), length);
+      this->handle_reply_(this->recv_buf_.data(), to_store);
       break;
     default:
       ESP_LOGW(TAG, "Unexpected response type: 0x%.2X", response_type);

esphome/components/host/preferences.cpp

@@ -4,6 +4,7 @@
 #include <fstream>
 #include "preferences.h"
 #include "esphome/core/application.h"
+#include "esphome/core/log.h"
 
 namespace esphome {
 namespace host {
@@ -14,7 +15,12 @@ static const char *const TAG = "host.preferences";
 void HostPreferences::setup_() {
   if (this->setup_complete_)
     return;
-  this->filename_.append(getenv("HOME"));
+  const char *home = getenv("HOME");
+  if (home == nullptr) {
+    ESP_LOGE(TAG, "HOME environment variable is not set");
+    abort();
+  }
+  this->filename_.append(home);
   this->filename_.append("/.esphome");
   this->filename_.append("/prefs");
   fs::create_directories(this->filename_);
@@ -44,9 +50,12 @@ void HostPreferences::setup_() {
 bool HostPreferences::sync() {
   this->setup_();
   FILE *fp = fopen(this->filename_.c_str(), "wb");
-  std::map<uint32_t, std::vector<uint8_t>>::iterator it;
+  if (fp == nullptr) {
+    ESP_LOGE(TAG, "Failed to open preferences file for writing: %s", this->filename_.c_str());
+    return false;
+  }
 
-  for (it = this->data.begin(); it != this->data.end(); ++it) {
+  for (auto it = this->data.begin(); it != this->data.end(); ++it) {
     fwrite(&it->first, sizeof(uint32_t), 1, fp);
     uint8_t len = it->second.size();
     fwrite(&len, sizeof(len), 1, fp);

esphome/components/max6956/max6956.cpp

@@ -111,6 +111,8 @@ void MAX6956::write_brightness_mode() {
 }
 
 void MAX6956::set_pin_brightness(uint8_t pin, float brightness) {
+  if (pin < MAX6956_MIN || pin > MAX6956_MAX)
+    return;
   uint8_t reg_addr = MAX6956_CURRENT_START + (pin - MAX6956_MIN) / 2;
   uint8_t config = 0;
   uint8_t shift = 4 * (pin % 2);

esphome/components/mdns/mdns_component.cpp

@@ -59,7 +59,7 @@ void MDNSComponent::compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUN
     service.proto = MDNS_STR(SERVICE_TCP);
     service.port = api::global_api_server->get_port();
 
-    const std::string &friendly_name = App.get_friendly_name();
+    const auto &friendly_name = App.get_friendly_name();
     bool friendly_name_empty = friendly_name.empty();
 
     // Calculate exact capacity for txt_records

esphome/components/mipi_dsi/mipi_dsi.cpp

@@ -10,7 +10,7 @@ namespace mipi_dsi {
 static constexpr size_t MIPI_DSI_MAX_CMD_LOG_BYTES = 64;
 
 static bool notify_refresh_ready(esp_lcd_panel_handle_t panel, esp_lcd_dpi_panel_event_data_t *edata, void *user_ctx) {
-  auto *sem = static_cast<SemaphoreHandle_t *>(user_ctx);
+  auto sem = static_cast<SemaphoreHandle_t>(user_ctx);
   BaseType_t need_yield = pdFALSE;
   xSemaphoreGiveFromISR(sem, &need_yield);
   return (need_yield == pdTRUE);
@@ -190,6 +190,7 @@ void MIPI_DSI::draw_pixels_at(int x_start, int y_start, int w, int h, const uint
   if (bitness != this->color_depth_) {
     display::Display::draw_pixels_at(x_start, y_start, w, h, ptr, order, bitness, big_endian, x_offset, y_offset,
                                      x_pad);
+    return;
   }
   this->write_to_display_(x_start, y_start, w, h, ptr, x_offset, y_offset, x_pad);
 }

esphome/components/mqtt/mqtt_component.cpp

@@ -209,12 +209,11 @@ bool MQTTComponent::send_discovery_() {
 
         if (this->is_disabled_by_default_())
           root[MQTT_ENABLED_BY_DEFAULT] = false;
-        // NOLINTBEGIN(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
-        const auto icon_ref = this->get_icon_ref_();
-        if (!icon_ref.empty()) {
-          root[MQTT_ICON] = icon_ref;
+        char icon_buf[MAX_ICON_LENGTH];
+        const char *icon = this->get_icon_to_(icon_buf);
+        if (icon[0] != '\0') {
+          root[MQTT_ICON] = icon;
         }
-        // NOLINTEND(clang-analyzer-cplusplus.NewDeleteLeaks)
 
         const auto entity_category = this->get_entity()->get_entity_category();
         if (entity_category != ENTITY_CATEGORY_NONE) {
@@ -268,7 +267,7 @@ bool MQTTComponent::send_discovery_() {
           root[MQTT_UNIQUE_ID] = unique_id_buf;
         }
 
-        const std::string &node_name = App.get_name();
+        const auto &node_name = App.get_name();
         if (discovery_info.object_id_generator == MQTT_DEVICE_NAME_OBJECT_ID_GENERATOR) {
           // node_name (max 31) + "_" (1) + object_id (max 128) + null
           char object_id_full[ESPHOME_DEVICE_NAME_MAX_LEN + 1 + OBJECT_ID_MAX_LEN + 1];
@@ -276,8 +275,8 @@ bool MQTTComponent::send_discovery_() {
           root[MQTT_OBJECT_ID] = object_id_full;
         }
 
-        const std::string &friendly_name_ref = App.get_friendly_name();
-        const std::string &node_friendly_name = friendly_name_ref.empty() ? node_name : friendly_name_ref;
+        const auto &friendly_name_ref = App.get_friendly_name();
+        const auto &node_friendly_name = friendly_name_ref.empty() ? node_name : friendly_name_ref;
         const char *node_area = App.get_area();
 
         JsonObject device_info = root[MQTT_DEVICE].to<JsonObject>();
@@ -413,7 +412,6 @@ const StringRef &MQTTComponent::friendly_name_() const { return this->get_entity
 StringRef MQTTComponent::get_default_object_id_to_(std::span<char, OBJECT_ID_MAX_LEN> buf) const {
   return this->get_entity()->get_object_id_to(buf);
 }
-StringRef MQTTComponent::get_icon_ref_() const { return this->get_entity()->get_icon_ref(); }
 bool MQTTComponent::is_disabled_by_default_() const { return this->get_entity()->is_disabled_by_default(); }
 bool MQTTComponent::compute_is_internal_() {
   if (this->custom_state_topic_.has_value()) {

esphome/components/mqtt/mqtt_component.h

@@ -298,8 +298,8 @@ class MQTTComponent : public Component {
   /// Get the friendly name of this MQTT component.
   const StringRef &friendly_name_() const;
 
-  /// Get the icon field of this component as StringRef
-  StringRef get_icon_ref_() const;
+  /// Get the icon field of this component into a stack buffer
+  const char *get_icon_to_(std::span<char, MAX_ICON_LENGTH> buf) const { return this->get_entity()->get_icon_to(buf); }
 
   /// Get whether the underlying Entity is disabled by default
   bool is_disabled_by_default_() const;

esphome/components/openthread/openthread.cpp

@@ -132,7 +132,7 @@ void OpenThreadSrpComponent::setup() {
   // set the host name
   uint16_t size;
   char *existing_host_name = otSrpClientBuffersGetHostNameString(instance, &size);
-  const std::string &host_name = App.get_name();
+  const auto &host_name = App.get_name();
   uint16_t host_name_len = host_name.size();
   if (host_name_len > size) {
     ESP_LOGW(TAG, "Hostname is too long, choose a shorter project name");

esphome/components/openthread/openthread.h

@@ -90,7 +90,7 @@ class InstanceLock {
   otInstance *get_instance();
 
  private:
-  // Use a private constructor in order to force thehandling
+  // Use a private constructor in order to force the handling
   // of acquisition failure
   InstanceLock() {}
 };

esphome/components/openthread/openthread_esp.cpp

@@ -197,6 +197,7 @@ network::IPAddresses OpenThreadComponent::get_ip_addresses() {
   esp_netif_t *netif = esp_netif_get_default_netif();
   count = esp_netif_get_all_ip6(netif, if_ip6s);
   assert(count <= CONFIG_LWIP_IPV6_NUM_ADDRESSES);
+  assert(count < addresses.size());
   for (int i = 0; i < count; i++) {
     addresses[i + 1] = network::IPAddress(&if_ip6s[i]);
   }

esphome/components/rp2040/boards.jinja2

@@ -0,0 +1,25 @@
+# Auto-generated by generate_boards.py — do not edit manually
+# To regenerate: python esphome/components/rp2040/generate_boards.py <arduino-pico-path>
+
+# arduino-pico maps pins >= {{ cyw43_gpio_offset }} to CYW43 wireless chip GPIOs
+CYW43_GPIO_OFFSET = {{ cyw43_gpio_offset }}
+CYW43_MAX_GPIO = {{ cyw43_max_gpio }}
+DEFAULT_MAX_PIN = {{ default_max_pin }}
+
+RP2040_BASE_PINS = {}
+
+RP2040_BOARD_PINS = {
+{%- for name, pins in board_pins %}
+    {{ name | repr }}: {{ pins | format_pins }},
+{%- endfor %}
+}
+
+BOARDS = {
+{%- for name, info in boards %}
+    {{ name | repr }}: {
+    {%- for key, value in info.items() %}
+        {{ key | repr }}: {{ value | repr }},
+    {%- endfor %}
+    },
+{%- endfor %}
+}

esphome/components/rp2040/generate_boards.py

@@ -0,0 +1,186 @@
+"""Generate boards.py from arduino-pico board definitions.
+
+Usage: python esphome/components/rp2040/generate_boards.py <arduino-pico-path>
+"""
+
+import json
+from pathlib import Path
+import re
+import sys
+
+from jinja2 import Environment, FileSystemLoader
+
+# Map arduino-pico pin defines to ESPHome-friendly names
+PIN_NAME_MAP = {
+    "LED": "LED",
+    "WIRE0_SDA": "SDA",
+    "WIRE0_SCL": "SCL",
+    "WIRE1_SDA": "SDA1",
+    "WIRE1_SCL": "SCL1",
+    "SPI0_MISO": "MISO",
+    "SPI0_MOSI": "MOSI",
+    "SPI0_SCK": "SCK",
+    "SPI0_SS": "SS",
+    "SERIAL1_TX": "TX",
+    "SERIAL1_RX": "RX",
+}
+
+# arduino-pico maps pins >= 64 to CYW43 wireless chip GPIOs (pin - 64)
+CYW43_GPIO_OFFSET = 64
+# CYW43 has 3 GPIOs: 0=LED, 1=VBUS_SENSE, 2=REG_ON
+CYW43_GPIO_COUNT = 3
+
+# Max GPIO pin per MCU (hardware specs from datasheets)
+MCU_MAX_PIN = {
+    "rp2040": 29,  # GPIO 0-29
+    "rp2350": 47,  # GPIO 0-47 (RP2350A)
+}
+DEFAULT_MAX_PIN = 29
+
+PIN_DEFINE_RE = re.compile(r"#define\s+PIN_(\w+)\s+\((\d+)u\)")
+
+
+def parse_variant_pins(variant_dir: Path) -> dict[str, int]:
+    """Parse pins_arduino.h and return mapped pin names."""
+    header = variant_dir / "pins_arduino.h"
+    if not header.exists():
+        return {}
+
+    pins = {}
+    for match in PIN_DEFINE_RE.finditer(header.read_text(encoding="utf-8")):
+        raw_name = match.group(1)
+        value = int(match.group(2))
+        if raw_name in PIN_NAME_MAP:
+            pins[PIN_NAME_MAP[raw_name]] = value
+    return pins
+
+
+def load_boards(arduino_pico_path: Path) -> tuple[dict, dict]:
+    """Load all board definitions and return (board_pins, boards) dicts."""
+    json_dir = arduino_pico_path / "tools" / "json"
+    variants_dir = arduino_pico_path / "variants"
+
+    board_pins = {}
+    boards = {}
+    variant_pins_cache: dict[str, dict[str, int]] = {}
+
+    for json_file in sorted(json_dir.glob("*.json")):
+        board_name = json_file.stem
+        with open(json_file, encoding="utf-8") as f:
+            data = json.load(f)
+
+        build = data.get("build", {})
+        mcu = build.get("mcu", "rp2040")
+        variant = build.get("variant", board_name)
+        name = data.get("name", board_name)
+        vendor = data.get("vendor", "")
+
+        display_name = f"{vendor} {name}".strip() if vendor else name
+
+        boards[board_name] = {
+            "name": display_name,
+            "mcu": mcu,
+            "max_pin": MCU_MAX_PIN.get(mcu, DEFAULT_MAX_PIN),
+        }
+
+        # Get pins for this variant
+        if variant not in variant_pins_cache:
+            variant_dir = variants_dir / variant
+            variant_pins_cache[variant] = parse_variant_pins(variant_dir)
+
+        pins = variant_pins_cache[variant]
+        if pins:
+            max_pin = boards[board_name]["max_pin"]
+            cyw43_max = CYW43_GPIO_OFFSET + CYW43_GPIO_COUNT - 1
+            # Filter out placeholder values (e.g. 99 = "not connected")
+            filtered = {
+                name: value
+                for name, value in pins.items()
+                if value <= max_pin or CYW43_GPIO_OFFSET <= value <= cyw43_max
+            }
+            if filtered:
+                board_pins[board_name] = filtered
+
+    # Compute max_virtual_pin per board from pin maps
+    for board_name, pins in board_pins.items():
+        if isinstance(pins, str):
+            continue
+        virtual_pins = [v for v in pins.values() if v >= CYW43_GPIO_OFFSET]
+        if virtual_pins and board_name in boards:
+            boards[board_name]["max_virtual_pin"] = max(virtual_pins)
+
+    # Deduplicate: if board pins match its variant's pins, use string alias
+    for board_name in list(board_pins.keys()):
+        if board_name not in boards:
+            continue
+        build_variant = _get_variant(json_dir / f"{board_name}.json")
+        if (
+            build_variant
+            and build_variant != board_name
+            and build_variant in board_pins
+            and board_pins[board_name] == board_pins[build_variant]
+        ):
+            board_pins[board_name] = build_variant
+
+    return board_pins, boards
+
+
+def _get_variant(json_file: Path) -> str | None:
+    """Get variant name from a board JSON file."""
+    if not json_file.exists():
+        return None
+    with open(json_file, encoding="utf-8") as f:
+        data = json.load(f)
+    return data.get("build", {}).get("variant")
+
+
+_TEMPLATE_DIR = Path(__file__).parent
+
+
+def _format_pins(pins: dict[str, int] | str) -> str:
+    """Jinja2 filter to format a pin dict or alias as Python source."""
+    if isinstance(pins, str):
+        return repr(pins)
+    items = ", ".join(f"{k!r}: {v}" for k, v in sorted(pins.items()))
+    return f"{{{items}}}"
+
+
+_jinja_env = Environment(
+    loader=FileSystemLoader(_TEMPLATE_DIR), keep_trailing_newline=True
+)
+_jinja_env.filters["format_pins"] = _format_pins
+_jinja_env.filters["repr"] = repr
+
+
+def generate(arduino_pico_path: Path) -> str:
+    """Generate boards.py content."""
+    board_pins, boards = load_boards(arduino_pico_path)
+
+    template = _jinja_env.get_template("boards.jinja2")
+    return template.render(
+        cyw43_gpio_offset=CYW43_GPIO_OFFSET,
+        cyw43_max_gpio=CYW43_GPIO_OFFSET + CYW43_GPIO_COUNT - 1,
+        default_max_pin=DEFAULT_MAX_PIN,
+        board_pins=sorted(board_pins.items()),
+        boards=sorted(boards.items()),
+    )
+
+
+def main():
+    if len(sys.argv) < 2:
+        print(f"Usage: {sys.argv[0]} <arduino-pico-path>", file=sys.stderr)
+        sys.exit(1)
+
+    arduino_pico_path = Path(sys.argv[1])
+    if not (arduino_pico_path / "tools" / "json").exists():
+        print(f"Error: {arduino_pico_path}/tools/json not found", file=sys.stderr)
+        sys.exit(1)
+
+    output = generate(arduino_pico_path)
+    output_file = Path(__file__).parent / "boards.py"
+    output_file.write_text(output, encoding="utf-8")
+    print(f"Generated {output_file}")
+
+
+if __name__ == "__main__":
+    main()

esphome/components/rp2040/gpio.py

@@ -54,19 +54,29 @@ def _translate_pin(value):
     return _lookup_pin(value)
 
 
+def _board_max_virtual_pin(board):
+    """Get the max CYW43 virtual pin for this board, or None if no virtual pins."""
+    return boards.BOARDS.get(board, {}).get("max_virtual_pin")
+
+
 def validate_gpio_pin(value):
     value = _translate_pin(value)
     board = CORE.data[KEY_RP2040][KEY_BOARD]
-    if board == "rpipicow" and value == 32:
-        return value  # Special case for Pico-w LED pin
-    if value < 0 or value > 29:
-        raise cv.Invalid(f"RP2040: Invalid pin number: {value}")
+    max_virtual = _board_max_virtual_pin(board)
+    if max_virtual is not None and boards.CYW43_GPIO_OFFSET <= value <= max_virtual:
+        return value
+    max_pin = boards.BOARDS.get(board, {}).get("max_pin", boards.DEFAULT_MAX_PIN)
+    if value < 0 or value > max_pin:
+        raise cv.Invalid(f"Invalid pin number: {value} (max {max_pin} for this board)")
     return value
 
 
 def validate_supports(value):
     board = CORE.data[KEY_RP2040][KEY_BOARD]
-    if board != "rpipicow" or value[CONF_NUMBER] != 32:
+    if (
+        _board_max_virtual_pin(board) is None
+        or value[CONF_NUMBER] < boards.CYW43_GPIO_OFFSET
+    ):
         return value
     mode = value[CONF_MODE]
     is_input = mode[CONF_INPUT]
@@ -75,7 +85,7 @@ def validate_supports(value):
     is_pullup = mode[CONF_PULLUP]
     is_pulldown = mode[CONF_PULLDOWN]
     if not is_output or is_input or is_open_drain or is_pullup or is_pulldown:
-        raise cv.Invalid("Only output mode is supported for Pico-w LED pin")
+        raise cv.Invalid("Only output mode is supported for CYW43 virtual pins")
     return value
 
 

esphome/components/sx126x/sx126x.cpp

@@ -155,7 +155,8 @@ void SX126x::configure() {
   }
 
   // check silicon version to make sure hw is ok
-  this->read_register_(REG_VERSION_STRING, (uint8_t *) this->version_, 16);
+  this->read_register_(REG_VERSION_STRING, (uint8_t *) this->version_, sizeof(this->version_));
+  this->version_[sizeof(this->version_) - 1] = '\0';
   if (strncmp(this->version_, "SX126", 5) != 0 && strncmp(this->version_, "LLCC68", 6) != 0) {
     this->mark_failed();
     return;

esphome/components/sx127x/sx127x.cpp

@@ -260,6 +260,11 @@ SX127xError SX127x::transmit_packet(const std::vector<uint8_t> &packet) {
     return SX127xError::INVALID_PARAMS;
   }
 
+  if (this->dio0_pin_ == nullptr) {
+    ESP_LOGE(TAG, "DIO0 pin not configured, cannot wait for transmit completion");
+    return SX127xError::INVALID_PARAMS;
+  }
+
   SX127xError ret = SX127xError::NONE;
   if (this->modulation_ == MOD_LORA) {
     this->set_mode_standby();

esphome/components/uart/uart_component.h

@@ -183,10 +183,10 @@ class UARTComponent {
   virtual void check_logger_conflict() = 0;
   bool check_read_timeout_(size_t len = 1);
 
-  InternalGPIOPin *tx_pin_;
-  InternalGPIOPin *rx_pin_;
-  InternalGPIOPin *flow_control_pin_;
-  size_t rx_buffer_size_;
+  InternalGPIOPin *tx_pin_{};
+  InternalGPIOPin *rx_pin_{};
+  InternalGPIOPin *flow_control_pin_{};
+  size_t rx_buffer_size_{};
   size_t rx_full_threshold_{1};
   size_t rx_timeout_{0};
   uint32_t baud_rate_{0};

esphome/components/web_server/web_server.cpp

@@ -568,7 +568,8 @@ static void set_json_id(JsonObject &root, EntityBase *obj, const char *prefix, J
     }
 #endif
 #ifdef USE_ENTITY_ICON
-    root[ESPHOME_F("icon")] = obj->get_icon_ref().c_str();
+    char icon_buf[MAX_ICON_LENGTH];
+    root[ESPHOME_F("icon")] = obj->get_icon_to(icon_buf);
 #endif
     root[ESPHOME_F("entity_category")] = obj->get_entity_category();
     bool is_disabled = obj->is_disabled_by_default();

esphome/components/web_server/web_server_v1.cpp

@@ -75,7 +75,7 @@ void WebServer::set_js_url(const char *js_url) { this->js_url_ = js_url; }
 
 void WebServer::handle_index_request(AsyncWebServerRequest *request) {
   AsyncResponseStream *stream = request->beginResponseStream(ESPHOME_F("text/html"));
-  const std::string &title = App.get_name();
+  const auto &title = App.get_name();
   stream->print(ESPHOME_F("<!DOCTYPE html><html lang=\"en\"><head><meta charset=UTF-8><meta "
                           "name=viewport content=\"width=device-width, initial-scale=1,user-scalable=no\"><title>"));
   stream->print(title.c_str());

esphome/components/wifi/wifi_component.cpp

@@ -913,7 +913,7 @@ void WiFiComponent::setup_ap_config_() {
     static constexpr size_t AP_SSID_PREFIX_LEN = 25;
     static constexpr size_t AP_SSID_SUFFIX_LEN = 7;
 
-    const std::string &app_name = App.get_name();
+    const auto &app_name = App.get_name();
     const char *name_ptr = app_name.c_str();
     size_t name_len = app_name.length();
 

esphome/components/wifi/wifi_component_esp8266.cpp

@@ -6,6 +6,7 @@
 
 #include <user_interface.h>
 
+#include <cassert>
 #include <utility>
 #include <algorithm>
 #ifdef USE_WIFI_WPA2_EAP
@@ -205,12 +206,13 @@ network::IPAddresses WiFiComponent::wifi_sta_ip_addresses() {
   network::IPAddresses addresses;
   uint8_t index = 0;
   for (auto &addr : addrList) {
+    assert(index < addresses.size());
     addresses[index++] = addr.ipFromNetifNum();
   }
   return addresses;
 }
 bool WiFiComponent::wifi_apply_hostname_() {
-  const std::string &hostname = App.get_name();
+  const auto &hostname = App.get_name();
   bool ret = wifi_station_set_hostname(const_cast<char *>(hostname.c_str()));
   if (!ret) {
     ESP_LOGV(TAG, "Set hostname failed");

esphome/components/wifi/wifi_component_esp_idf.cpp

@@ -585,6 +585,7 @@ network::IPAddresses WiFiComponent::wifi_sta_ip_addresses() {
   uint8_t count = 0;
   count = esp_netif_get_all_ip6(s_sta_netif, if_ip6s);
   assert(count <= CONFIG_LWIP_IPV6_NUM_ADDRESSES);
+  assert(count < addresses.size());
   for (int i = 0; i < count; i++) {
     addresses[i + 1] = network::IPAddress(&if_ip6s[i]);
   }

esphome/components/wifi/wifi_component_pico_w.cpp

@@ -3,6 +3,8 @@
 #ifdef USE_WIFI
 #ifdef USE_RP2040
 
+#include <cassert>
+
 #include "lwip/dns.h"
 #include "lwip/err.h"
 #include "lwip/netif.h"
@@ -285,6 +287,7 @@ network::IPAddresses WiFiComponent::wifi_sta_ip_addresses() {
     if (ip == ap_ip) {
       continue;
     }
+    assert(index < addresses.size());
     addresses[index++] = ip;
   }
   return addresses;

esphome/config_validation.py

@@ -400,14 +400,21 @@ def string_strict(value):
 
 def icon(value):
     """Validate that a given config value is a valid icon."""
+    from esphome.core.config import ICON_MAX_LENGTH
+
     value = string_strict(value)
     if not value:
         return value
-    if re.match("^[\\w\\-]+:[\\w\\-]+$", value):
-        return value
-    raise Invalid(
-        'Icons must match the format "[icon pack]:[icon]", e.g. "mdi:home-assistant"'
-    )
+    if not re.match("^[\\w\\-]+:[\\w\\-]+$", value):
+        raise Invalid(
+            'Icons must match the format "[icon pack]:[icon]", e.g. "mdi:home-assistant"'
+        )
+    if len(value) > ICON_MAX_LENGTH:
+        raise Invalid(
+            f"Icon string is too long ({len(value)} chars, max {ICON_MAX_LENGTH}). "
+            "Icons are stored in PROGMEM with a 64-byte buffer limit."
+        )
+    return value
 
 
 def sub_device_id(value: str | None) -> core.ID | None:

esphome/core/application.h

@@ -138,26 +138,36 @@ static constexpr uint32_t TEARDOWN_TIMEOUT_REBOOT_MS = 1000;  // 1 second for qu
 
 class Application {
  public:
-  void pre_setup(const std::string &name, const std::string &friendly_name, bool name_add_mac_suffix) {
+#ifdef ESPHOME_NAME_ADD_MAC_SUFFIX
+  /// Pre-setup with MAC suffix: overwrites placeholder in mutable static buffers with actual MAC.
+  void pre_setup(char *name, size_t name_len, char *friendly_name, size_t friendly_name_len) {
     arch_init();
-    this->name_add_mac_suffix_ = name_add_mac_suffix;
-    if (name_add_mac_suffix) {
-      // MAC address length: 12 hex chars + null terminator
-      constexpr size_t mac_address_len = 13;
-      // MAC address suffix length (last 6 characters of 12-char MAC address string)
-      constexpr size_t mac_address_suffix_len = 6;
-      char mac_addr[mac_address_len];
-      get_mac_address_into_buffer(mac_addr);
-      const char *mac_suffix_ptr = mac_addr + mac_address_suffix_len;
-      this->name_ = make_name_with_suffix(name, '-', mac_suffix_ptr, mac_address_suffix_len);
-      if (!friendly_name.empty()) {
-        this->friendly_name_ = make_name_with_suffix(friendly_name, ' ', mac_suffix_ptr, mac_address_suffix_len);
-      }
-    } else {
-      this->name_ = name;
-      this->friendly_name_ = friendly_name;
+    this->name_add_mac_suffix_ = true;
+    // MAC address length: 12 hex chars + null terminator
+    constexpr size_t mac_address_len = 13;
+    // MAC address suffix length (last 6 characters of 12-char MAC address string)
+    constexpr size_t mac_address_suffix_len = 6;
+    char mac_addr[mac_address_len];
+    get_mac_address_into_buffer(mac_addr);
+    // Overwrite the placeholder suffix in the mutable static buffers with actual MAC
+    // name is always non-empty (validated by validate_hostname in Python config)
+    memcpy(name + name_len - mac_address_suffix_len, mac_addr + mac_address_suffix_len, mac_address_suffix_len);
+    if (friendly_name_len > 0) {
+      memcpy(friendly_name + friendly_name_len - mac_address_suffix_len, mac_addr + mac_address_suffix_len,
+             mac_address_suffix_len);
     }
+    this->name_ = StringRef(name, name_len);
+    this->friendly_name_ = StringRef(friendly_name, friendly_name_len);
   }
+#else
+  /// Pre-setup without MAC suffix: StringRef points directly at const string literals in flash.
+  void pre_setup(const char *name, size_t name_len, const char *friendly_name, size_t friendly_name_len) {
+    arch_init();
+    this->name_add_mac_suffix_ = false;
+    this->name_ = StringRef(name, name_len);
+    this->friendly_name_ = StringRef(friendly_name, friendly_name_len);
+  }
+#endif
 
 #ifdef USE_DEVICES
   void register_device(Device *device) { this->devices_.push_back(device); }
@@ -274,10 +284,10 @@ class Application {
   void loop();
 
   /// Get the name of this Application set by pre_setup().
-  const std::string &get_name() const { return this->name_; }
+  const StringRef &get_name() const { return this->name_; }
 
   /// Get the friendly name of this Application set by pre_setup().
-  const std::string &get_friendly_name() const { return this->friendly_name_; }
+  const StringRef &get_friendly_name() const { return this->friendly_name_; }
 
   /// Get the area of this Application set by pre_setup().
   const char *get_area() const {
@@ -627,9 +637,9 @@ class Application {
 #endif
 #endif
 
-  // std::string members (typically 24-32 bytes each)
-  std::string name_;
-  std::string friendly_name_;
+  // StringRef members (8 bytes each: pointer + size)
+  StringRef name_;
+  StringRef friendly_name_;
 
   // 4-byte members
   uint32_t last_loop_{0};

esphome/core/config.py

@@ -50,6 +50,7 @@ from esphome.core import (
 )
 from esphome.helpers import (
     copy_file_if_changed,
+    cpp_string_escape,
     fnv1a_32bit_hash,
     get_str_env,
     walk_files,
@@ -58,6 +59,38 @@ from esphome.types import ConfigType
 
 _LOGGER = logging.getLogger(__name__)
 
+# C++ variable names and separators for app name buffers (used with MAC suffix)
+_APP_NAME_BUF_VAR = "esphome_app_name_buf"
+_APP_NAME_MAC_SEP = "-"
+_APP_FRIENDLY_NAME_BUF_VAR = "esphome_app_friendly_name_buf"
+_APP_FRIENDLY_NAME_MAC_SEP = " "
+# Placeholder suffix for MAC address (last 6 hex chars)
+_MAC_SUFFIX_PLACEHOLDER = "XXXXXX"
+
+
+def make_app_name_cpp(
+    value: str, var_name: str, sep: str, *, add_mac_suffix: bool
+) -> tuple[str, str | None, int]:
+    """Compute C++ expression and optional global declaration for an app name.
+
+    Returns (cpp_expr, global_decl_or_none, byte_length).
+    - cpp_expr: The C++ expression to pass to pre_setup (var name or string literal).
+    - global_decl: A static char[] declaration string, or None if not needed.
+    - byte_length: The UTF-8 byte length of the string value.
+    """
+    if add_mac_suffix:
+        buf_value = "" if not value else f"{value}{sep}{_MAC_SUFFIX_PLACEHOLDER}"
+        escaped = cpp_string_escape(buf_value)
+        return (
+            var_name,
+            f"static char {var_name}[] = {escaped};",
+            len(buf_value.encode("utf-8")),
+        )
+    if not value:
+        return '""', None, 0
+    return cpp_string_escape(value), None, len(value.encode("utf-8"))
+
+
 StartupTrigger = cg.esphome_ns.class_(
     "StartupTrigger", cg.Component, automation.Trigger.template()
 )
@@ -78,6 +111,8 @@ VALID_INCLUDE_EXTS = {".h", ".hpp", ".tcc", ".ino", ".cpp", ".c"}
 
 def validate_hostname(config):
     # Keep in sync with ESPHOME_DEVICE_NAME_MAX_LEN in esphome/core/entity_base.h
+    if not config[CONF_NAME]:
+        raise cv.Invalid("Hostname must not be empty", path=[CONF_NAME])
     max_length = 31
     if config[CONF_NAME_ADD_MAC_SUFFIX]:
         max_length -= 7  # "-AABBCC" is appended when add mac suffix option is used
@@ -188,6 +223,10 @@ else:
 # Keep in sync with ESPHOME_FRIENDLY_NAME_MAX_LEN in esphome/core/entity_base.h
 FRIENDLY_NAME_MAX_LEN = 120
 
+# Max icon string length (63 chars + null = 64-byte PROGMEM buffer)
+# Keep in sync with MAX_ICON_LENGTH in esphome/core/entity_base.h
+ICON_MAX_LENGTH = 63
+
 AREA_SCHEMA = cv.Schema(
     {
         cv.GenerateID(CONF_ID): cv.declare_id(Area),
@@ -551,13 +590,28 @@ async def to_code(config: ConfigType) -> None:
     # Construct App via placement new — see application.cpp for storage details
     cg.add_global(cg.RawStatement("#include <new>"))
     cg.add(cg.RawExpression("new (&App) Application()"))
-    cg.add(
-        cg.App.pre_setup(
-            config[CONF_NAME],
-            config[CONF_FRIENDLY_NAME],
-            config[CONF_NAME_ADD_MAC_SUFFIX],
+    name = config[CONF_NAME]
+    friendly_name = config[CONF_FRIENDLY_NAME]
+    name_add_mac_suffix = config[CONF_NAME_ADD_MAC_SUFFIX]
+
+    def _emit_app_name(
+        value: str, var_name: str, sep: str
+    ) -> tuple[cg.Expression, int]:
+        """Emit codegen for an app name and return (expression, byte_length)."""
+        cpp_expr, global_decl, byte_len = make_app_name_cpp(
+            value, var_name, sep, add_mac_suffix=name_add_mac_suffix
         )
+        if global_decl is not None:
+            cg.add_global(cg.RawStatement(global_decl))
+        return cg.RawExpression(cpp_expr), byte_len
+
+    name_expr, name_len = _emit_app_name(name, _APP_NAME_BUF_VAR, _APP_NAME_MAC_SEP)
+    friendly_expr, friendly_len = _emit_app_name(
+        friendly_name, _APP_FRIENDLY_NAME_BUF_VAR, _APP_FRIENDLY_NAME_MAC_SEP
     )
+    if name_add_mac_suffix:
+        cg.add_define("ESPHOME_NAME_ADD_MAC_SUFFIX")
+    cg.add(cg.App.pre_setup(name_expr, name_len, friendly_expr, friendly_len))
     # Define component count for static allocation
     cg.add_define("ESPHOME_COMPONENT_COUNT", len(CORE.component_ids))
 

esphome/core/defines.h

@@ -13,6 +13,7 @@
 #define ESPHOME_PROJECT_VERSION "v2"
 #define ESPHOME_PROJECT_VERSION_30 "v2"
 #define ESPHOME_VARIANT "ESP32"
+#define ESPHOME_NAME_ADD_MAC_SUFFIX
 #define ESPHOME_DEBUG_SCHEDULER
 #define ESPHOME_DEBUG_API
 
@@ -356,6 +357,8 @@
 #endif
 
 #ifdef USE_NRF52
+#define ESPHOME_BLE_NUS_TX_RING_BUFFER_SIZE 512
+#define ESPHOME_BLE_NUS_RX_RING_BUFFER_SIZE 512
 #define USE_ESPHOME_TASK_LOG_BUFFER
 #define USE_LOGGER_EARLY_MESSAGE
 #define USE_LOGGER_UART_SELECTION_USB_CDC

esphome/core/entity_base.cpp

@@ -1,6 +1,7 @@
 #include "esphome/core/entity_base.h"
 #include "esphome/core/application.h"
 #include "esphome/core/helpers.h"
+#include "esphome/core/progmem.h"
 #include "esphome/core/string_ref.h"
 
 namespace esphome {
@@ -22,13 +23,13 @@ void EntityBase::set_name(const char *name, uint32_t object_id_hash) {
       // Bug-for-bug compatibility with OLD behavior:
       // - With MAC suffix: OLD code used App.get_friendly_name() directly (no fallback)
       // - Without MAC suffix: OLD code used pre-computed object_id with fallback to device name
-      const std::string &friendly = App.get_friendly_name();
+      const auto &friendly = App.get_friendly_name();
       if (App.is_name_add_mac_suffix_enabled()) {
         // MAC suffix enabled - use friendly_name directly (even if empty) for compatibility
-        this->name_ = StringRef(friendly);
+        this->name_ = friendly;
       } else {
         // No MAC suffix - fallback to device name if friendly_name is empty
-        this->name_ = StringRef(!friendly.empty() ? friendly : App.get_name());
+        this->name_ = !friendly.empty() ? friendly : App.get_name();
       }
     }
     this->flags_.has_own_name = false;
@@ -72,7 +73,27 @@ std::string EntityBase::get_unit_of_measurement() const {
   return std::string(this->get_unit_of_measurement_ref().c_str());
 }
 
-// Entity icon (from index)
+// Entity icon — buffer-based API for PROGMEM safety on ESP8266
+const char *EntityBase::get_icon_to([[maybe_unused]] std::span<char, MAX_ICON_LENGTH> buffer) const {
+#ifdef USE_ENTITY_ICON
+  const uint8_t idx = this->icon_idx_;
+#else
+  const uint8_t idx = 0;
+#endif
+#ifdef USE_ESP8266
+  if (idx == 0)
+    return "";
+  const char *icon = entity_icon_lookup(idx);
+  ESPHOME_strncpy_P(buffer.data(), icon, buffer.size() - 1);
+  buffer[buffer.size() - 1] = '\0';
+  return buffer.data();
+#else
+  return entity_icon_lookup(idx);
+#endif
+}
+
+#ifndef USE_ESP8266
+// Deprecated icon accessors — not available on ESP8266 (rodata is RAM)
 StringRef EntityBase::get_icon_ref() const {
 #ifdef USE_ENTITY_ICON
   return StringRef(entity_icon_lookup(this->icon_idx_));
@@ -80,7 +101,14 @@ StringRef EntityBase::get_icon_ref() const {
   return StringRef(entity_icon_lookup(0));
 #endif
 }
-std::string EntityBase::get_icon() const { return std::string(this->get_icon_ref().c_str()); }
+std::string EntityBase::get_icon() const {
+#ifdef USE_ENTITY_ICON
+  return std::string(entity_icon_lookup(this->icon_idx_));
+#else
+  return std::string(entity_icon_lookup(0));
+#endif
+}
+#endif  // !USE_ESP8266
 
 // Entity Object ID - computed on-demand from name
 std::string EntityBase::get_object_id() const {
@@ -154,8 +182,10 @@ ESPPreferenceObject EntityBase::make_entity_preference_(size_t size, uint32_t ve
 
 #ifdef USE_ENTITY_ICON
 void log_entity_icon(const char *tag, const char *prefix, const EntityBase &obj) {
-  if (!obj.get_icon_ref().empty()) {
-    ESP_LOGCONFIG(tag, "%s  Icon: '%s'", prefix, obj.get_icon_ref().c_str());
+  char icon_buf[MAX_ICON_LENGTH];
+  const char *icon = obj.get_icon_to(icon_buf);
+  if (icon[0] != '\0') {
+    ESP_LOGCONFIG(tag, "%s  Icon: '%s'", prefix, icon);
   }
 }
 #endif

esphome/core/entity_base.h

@@ -36,6 +36,10 @@ static constexpr size_t OBJECT_ID_MAX_LEN = 128;
 // Maximum state length that Home Assistant will accept without raising ValueError
 static constexpr size_t MAX_STATE_LEN = 255;
 
+// Maximum icon string buffer size (63 chars + null terminator)
+// Icons are stored in PROGMEM; on ESP8266 they must be copied to a stack buffer.
+static constexpr size_t MAX_ICON_LENGTH = 64;
+
 enum EntityCategory : uint8_t {
   ENTITY_CATEGORY_NONE = 0,
   ENTITY_CATEGORY_CONFIG = 1,
@@ -124,12 +128,31 @@ class EntityBase {
                 "2026.3.0")
   std::string get_unit_of_measurement() const;
 
-  // Get/set this entity's icon
-  ESPDEPRECATED(
-      "Use get_icon_ref() instead for better performance (avoids string copy). Will be removed in ESPHome 2026.5.0",
-      "2025.11.0")
-  std::string get_icon() const;
+  // Get this entity's icon into a stack buffer.
+  // On ESP32: returns pointer to PROGMEM string directly (buffer unused).
+  // On ESP8266: copies from PROGMEM to buffer, returns buffer pointer.
+  const char *get_icon_to(std::span<char, MAX_ICON_LENGTH> buffer) const;
+
+#ifdef USE_ESP8266
+  // On ESP8266, rodata is RAM. Icons are in PROGMEM and cannot be accessed
+  // directly as const char*. Use get_icon_to() with a stack buffer instead.
+  template<typename T = int> StringRef get_icon_ref() const {
+    static_assert(sizeof(T) == 0,
+                  "get_icon_ref() unavailable on ESP8266 (rodata is RAM). Use get_icon_to() with a stack buffer.");
+    return StringRef("");
+  }
+  template<typename T = int> std::string get_icon() const {
+    static_assert(sizeof(T) == 0,
+                  "get_icon() unavailable on ESP8266 (rodata is RAM). Use get_icon_to() with a stack buffer.");
+    return "";
+  }
+#else
+  // Deprecated: use get_icon_to() instead. Icons are in PROGMEM.
+  ESPDEPRECATED("Use get_icon_to() instead. Will be removed in ESPHome 2026.9.0", "2026.3.0")
   StringRef get_icon_ref() const;
+  ESPDEPRECATED("Use get_icon_to() instead. Will be removed in ESPHome 2026.9.0", "2026.3.0")
+  std::string get_icon() const;
+#endif
 
 #ifdef USE_DEVICES
   // Get/set this entity's device id

esphome/core/entity_helpers.py

@@ -17,6 +17,7 @@ from esphome.const import (
     CONF_UNIT_OF_MEASUREMENT,
 )
 from esphome.core import CORE, ID, CoroPriority, coroutine_with_priority
+from esphome.core.config import ICON_MAX_LENGTH
 from esphome.cpp_generator import MockObj, RawStatement, add, get_variable
 import esphome.final_validate as fv
 from esphome.helpers import cpp_string_escape, fnv1_hash_object_id, sanitize, snake_case
@@ -78,6 +79,8 @@ def _generate_category_code(
     table_var: str,
     lookup_fn: str,
     strings: dict[str, int],
+    *,
+    progmem_strings: bool = False,
 ) -> str:
     """Generate C++ code for one string category (PROGMEM pointer table + lookup).
 
@@ -85,14 +88,40 @@ def _generate_category_code(
     in flash (via PROGMEM) and read with progmem_read_ptr(). String literals
     themselves remain in RAM but benefit from linker string deduplication.
     Index 0 means "not set" and returns empty string.
+
+    When progmem_strings=True, each string is declared as a separate PROGMEM
+    char array. This ensures the string data itself is in flash on ESP8266
+    (where .rodata is RAM). On other platforms PROGMEM is a no-op.
     """
     if not strings:
         return ""
 
     sorted_strings = sorted(strings.items(), key=lambda x: x[1])
-    entries = ", ".join(cpp_string_escape(s) for s, _ in sorted_strings)
     count = len(sorted_strings)
 
+    if progmem_strings:
+        # Emit individual PROGMEM char arrays so string data lives in flash
+        lines: list[str] = []
+        var_names: list[str] = []
+        for i, (s, _) in enumerate(sorted_strings):
+            var_name = f"{table_var}_STR_{i}"
+            var_names.append(var_name)
+            lines.append(
+                f"static const char {var_name}[] PROGMEM = {cpp_string_escape(s)};"
+            )
+        entries = ", ".join(var_names)
+        # Empty string must also be PROGMEM — on ESP8266, callers use strncpy_P
+        empty_var = f"{table_var}_EMPTY"
+        lines.append(f'static const char {empty_var}[] PROGMEM = "";')
+        lines.append(f"static const char *const {table_var}[] PROGMEM = {{{entries}}};")
+        lines.append(f"const char *{lookup_fn}(uint8_t index) {{")
+        lines.append(f"  if (index == 0 || index > {count}) return {empty_var};")
+        lines.append(f"  return progmem_read_ptr(&{table_var}[index - 1]);")
+        lines.append("}")
+        return "\n".join(lines) + "\n"
+
+    entries = ", ".join(cpp_string_escape(s) for s, _ in sorted_strings)
+
     return (
         f"static const char *const {table_var}[] PROGMEM = {{{entries}}};\n"
         f"const char *{lookup_fn}(uint8_t index) {{\n"
@@ -103,9 +132,9 @@ def _generate_category_code(
 
 
 _CATEGORY_CONFIGS = (
-    ("ENTITY_DC_TABLE", "entity_device_class_lookup", "device_classes"),
-    ("ENTITY_UOM_TABLE", "entity_uom_lookup", "units"),
-    ("ENTITY_ICON_TABLE", "entity_icon_lookup", "icons"),
+    ("ENTITY_DC_TABLE", "entity_device_class_lookup", "device_classes", False),
+    ("ENTITY_UOM_TABLE", "entity_uom_lookup", "units", False),
+    ("ENTITY_ICON_TABLE", "entity_icon_lookup", "icons", True),
 )
 
 
@@ -117,8 +146,10 @@ async def _generate_tables_job() -> None:
     """
     pool = _get_pool()
     parts = ["namespace esphome {"]
-    for table_var, lookup_fn, attr in _CATEGORY_CONFIGS:
-        code = _generate_category_code(table_var, lookup_fn, getattr(pool, attr))
+    for table_var, lookup_fn, attr, progmem_strs in _CATEGORY_CONFIGS:
+        code = _generate_category_code(
+            table_var, lookup_fn, getattr(pool, attr), progmem_strings=progmem_strs
+        )
         if code:
             parts.append(code)
     parts.append("}  // namespace esphome")
@@ -160,6 +191,10 @@ def register_unit_of_measurement(value: str) -> int:
 
 def register_icon(value: str) -> int:
     """Register an icon string and return its 1-based index."""
+    if value and len(value) > ICON_MAX_LENGTH:
+        raise ValueError(
+            f"Icon string too long ({len(value)} chars, max {ICON_MAX_LENGTH}): '{value}'"
+        )
     return _register_string(value, _get_pool().icons, _MAX_ICONS, "icon")
 
 

esphome/core/event_pool.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#if defined(USE_ESP32)
+#if defined(USE_ESP32) || defined(USE_ZEPHYR)
 
 #include <atomic>
 #include <cstddef>

tests/components/audio_file/common.yaml

@@ -3,3 +3,7 @@ audio_file:
     file:
       type: local
       path: $component_dir/test.wav
+
+media_source:
+  - platform: audio_file
+    id: audio_file_source

tests/components/ble_nus/test-uart.nrf52-adafruit.yaml

@@ -0,0 +1,4 @@
+ble_nus:
+  type: uart
+  tx_buffer_size: 160
+  rx_buffer_size: 160

tests/dummy_main.cpp

@@ -12,7 +12,9 @@
 using namespace esphome;
 
 void setup() {
-  App.pre_setup("livingroom", "LivingRoom", false);
+  static char name[] = "livingroom";
+  static char friendly_name[] = "LivingRoom";
+  App.pre_setup(name, sizeof(name) - 1, friendly_name, sizeof(friendly_name) - 1);
   auto *log = new logger::Logger(115200);  // NOLINT
   log->pre_setup();
   log->set_uart_selection(logger::UART_SELECTION_UART0);

tests/unit_tests/components/test_rp2040_generate_boards.py

@@ -0,0 +1,273 @@
+"""Tests for rp2040 generate_boards.py."""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+import textwrap
+
+import pytest
+
+from esphome.components.rp2040.generate_boards import load_boards, parse_variant_pins
+
+PICO_PINS_HEADER = textwrap.dedent("""\
+    #pragma once
+    #define PIN_LED        (25u)
+    #define PIN_SERIAL1_TX (0u)
+    #define PIN_SERIAL1_RX (1u)
+    #define PIN_WIRE0_SDA  (4u)
+    #define PIN_WIRE0_SCL  (5u)
+    #define PIN_WIRE1_SDA  (26u)
+    #define PIN_WIRE1_SCL  (27u)
+    #define PIN_SPI0_MISO  (16u)
+    #define PIN_SPI0_MOSI  (19u)
+    #define PIN_SPI0_SCK   (18u)
+    #define PIN_SPI0_SS    (17u)
+    #include "../generic/common.h"
+""")
+
+PICOW_PINS_HEADER = textwrap.dedent("""\
+    #pragma once
+    #include <cyw43_wrappers.h>
+    #define PIN_LED        (64u)
+    #define PIN_WIRE0_SDA  (4u)
+    #define PIN_WIRE0_SCL  (5u)
+    #include "../generic/common.h"
+""")
+
+
+@pytest.fixture()
+def arduino_pico(tmp_path: Path) -> Path:
+    """Create a minimal arduino-pico directory structure."""
+    json_dir = tmp_path / "tools" / "json"
+    json_dir.mkdir(parents=True)
+    variants_dir = tmp_path / "variants"
+    variants_dir.mkdir()
+
+    generic_dir = variants_dir / "generic"
+    generic_dir.mkdir()
+    (generic_dir / "common.h").write_text("#pragma once\n")
+
+    return tmp_path
+
+
+def _add_board(
+    arduino_pico: Path,
+    board_name: str,
+    mcu: str = "rp2040",
+    variant: str | None = None,
+    vendor: str = "",
+    name: str | None = None,
+    pins_header: str | None = None,
+) -> None:
+    """Add a board JSON and variant to the fake arduino-pico tree."""
+    if variant is None:
+        variant = board_name
+    if name is None:
+        name = board_name
+
+    json_dir = arduino_pico / "tools" / "json"
+    variants_dir = arduino_pico / "variants"
+
+    board_json = {
+        "build": {
+            "mcu": mcu,
+            "variant": variant,
+        },
+        "name": name,
+        "vendor": vendor,
+    }
+    (json_dir / f"{board_name}.json").write_text(json.dumps(board_json))
+
+    variant_dir = variants_dir / variant
+    variant_dir.mkdir(exist_ok=True)
+    if pins_header is not None:
+        (variant_dir / "pins_arduino.h").write_text(pins_header)
+
+
+def test_parse_basic_pins(tmp_path: Path) -> None:
+    variant_dir = tmp_path / "rpipico"
+    variant_dir.mkdir()
+    (variant_dir / "pins_arduino.h").write_text(PICO_PINS_HEADER)
+
+    pins = parse_variant_pins(variant_dir)
+    assert pins["LED"] == 25
+    assert pins["SDA"] == 4
+    assert pins["SCL"] == 5
+    assert pins["SDA1"] == 26
+    assert pins["SCL1"] == 27
+    assert pins["MISO"] == 16
+    assert pins["MOSI"] == 19
+    assert pins["SCK"] == 18
+    assert pins["SS"] == 17
+    assert pins["TX"] == 0
+    assert pins["RX"] == 1
+
+
+def test_parse_cyw43_led_pin(tmp_path: Path) -> None:
+    variant_dir = tmp_path / "rpipicow"
+    variant_dir.mkdir()
+    (variant_dir / "pins_arduino.h").write_text(PICOW_PINS_HEADER)
+
+    pins = parse_variant_pins(variant_dir)
+    assert pins["LED"] == 64
+
+
+def test_parse_missing_header(tmp_path: Path) -> None:
+    variant_dir = tmp_path / "noheader"
+    variant_dir.mkdir()
+    assert parse_variant_pins(variant_dir) == {}
+
+
+def test_parse_unmapped_defines_ignored(tmp_path: Path) -> None:
+    variant_dir = tmp_path / "custom"
+    variant_dir.mkdir()
+    (variant_dir / "pins_arduino.h").write_text(
+        "#define PIN_NEOPIXEL (16u)\n#define PIN_LED (25u)\n"
+    )
+
+    pins = parse_variant_pins(variant_dir)
+    assert "NEOPIXEL" not in pins
+    assert pins["LED"] == 25
+
+
+def test_load_basic_board(arduino_pico: Path) -> None:
+    _add_board(
+        arduino_pico,
+        "rpipico",
+        vendor="Raspberry Pi",
+        name="Pico",
+        pins_header=PICO_PINS_HEADER,
+    )
+
+    board_pins, boards = load_boards(arduino_pico)
+
+    assert "rpipico" in boards
+    assert boards["rpipico"]["name"] == "Raspberry Pi Pico"
+    assert boards["rpipico"]["mcu"] == "rp2040"
+    assert boards["rpipico"]["max_pin"] == 29
+
+    assert "rpipico" in board_pins
+    assert board_pins["rpipico"]["LED"] == 25
+    assert board_pins["rpipico"]["SDA"] == 4
+
+
+def test_load_rp2350_board(arduino_pico: Path) -> None:
+    _add_board(
+        arduino_pico,
+        "rpipico2",
+        mcu="rp2350",
+        vendor="Raspberry Pi",
+        name="Pico 2",
+        pins_header=PICO_PINS_HEADER,
+    )
+
+    _, boards = load_boards(arduino_pico)
+
+    assert boards["rpipico2"]["mcu"] == "rp2350"
+    assert boards["rpipico2"]["max_pin"] == 47
+
+
+def test_cyw43_board_has_max_virtual_pin(arduino_pico: Path) -> None:
+    _add_board(
+        arduino_pico,
+        "rpipicow",
+        vendor="Raspberry Pi",
+        name="Pico W",
+        pins_header=PICOW_PINS_HEADER,
+    )
+
+    _, boards = load_boards(arduino_pico)
+
+    assert boards["rpipicow"]["max_virtual_pin"] == 64
+
+
+def test_non_cyw43_board_has_no_max_virtual_pin(arduino_pico: Path) -> None:
+    _add_board(
+        arduino_pico,
+        "rpipico",
+        vendor="Raspberry Pi",
+        name="Pico",
+        pins_header=PICO_PINS_HEADER,
+    )
+
+    _, boards = load_boards(arduino_pico)
+
+    assert "max_virtual_pin" not in boards["rpipico"]
+
+
+def test_board_without_variant_header(arduino_pico: Path) -> None:
+    _add_board(arduino_pico, "novariant", name="No Variant")
+
+    board_pins, boards = load_boards(arduino_pico)
+
+    assert "novariant" in boards
+    assert "novariant" not in board_pins
+
+
+def test_shared_variant_deduplicates(arduino_pico: Path) -> None:
+    """Two boards sharing the same variant should alias."""
+    _add_board(arduino_pico, "base_board", pins_header=PICO_PINS_HEADER)
+    _add_board(arduino_pico, "alias_board", variant="base_board")
+
+    board_pins, _ = load_boards(arduino_pico)
+
+    assert board_pins["base_board"] == parse_variant_pins(
+        arduino_pico / "variants" / "base_board"
+    )
+    assert board_pins["alias_board"] == "base_board"
+
+
+def test_display_name_with_vendor(arduino_pico: Path) -> None:
+    _add_board(arduino_pico, "testboard", vendor="Acme", name="Widget")
+    _, boards = load_boards(arduino_pico)
+    assert boards["testboard"]["name"] == "Acme Widget"
+
+
+def test_display_name_without_vendor(arduino_pico: Path) -> None:
+    _add_board(arduino_pico, "testboard", vendor="", name="Widget")
+    _, boards = load_boards(arduino_pico)
+    assert boards["testboard"]["name"] == "Widget"
+
+
+def test_unknown_mcu_gets_default_max_pin(arduino_pico: Path) -> None:
+    _add_board(arduino_pico, "future", mcu="rp2450", pins_header=PICO_PINS_HEADER)
+    _, boards = load_boards(arduino_pico)
+    assert boards["future"]["max_pin"] == 29
+
+
+def test_placeholder_pins_filtered_out(arduino_pico: Path) -> None:
+    """Pins with placeholder values like 99 should be filtered out."""
+    header = textwrap.dedent("""\
+        #pragma once
+        #define PIN_LED        (25u)
+        #define PIN_WIRE0_SDA  (4u)
+        #define PIN_WIRE0_SCL  (5u)
+        #define PIN_WIRE1_SDA  (99u)
+        #define PIN_WIRE1_SCL  (99u)
+    """)
+    _add_board(arduino_pico, "placeholder", pins_header=header)
+
+    board_pins, boards = load_boards(arduino_pico)
+
+    assert "SDA1" not in board_pins["placeholder"]
+    assert "SCL1" not in board_pins["placeholder"]
+    assert board_pins["placeholder"]["LED"] == 25
+    assert "max_virtual_pin" not in boards["placeholder"]
+
+
+def test_placeholder_pins_not_treated_as_virtual(arduino_pico: Path) -> None:
+    """Pin 99 should not cause max_virtual_pin to be set."""
+    header = textwrap.dedent("""\
+        #pragma once
+        #define PIN_LED        (64u)
+        #define PIN_WIRE0_SDA  (4u)
+        #define PIN_WIRE0_SCL  (5u)
+        #define PIN_SPI0_MISO  (99u)
+    """)
+    _add_board(arduino_pico, "badpin", pins_header=header)
+
+    board_pins, boards = load_boards(arduino_pico)
+
+    assert "MISO" not in board_pins["badpin"]
+    assert boards["badpin"]["max_virtual_pin"] == 64

tests/unit_tests/core/test_config.py

@@ -23,6 +23,7 @@ from esphome.const import (
 from esphome.core import CORE, config
 from esphome.core.config import (
     Area,
+    make_app_name_cpp,
     preload_core_config,
     valid_include,
     valid_project_name,
@@ -969,3 +970,79 @@ def test_config_hash_different_for_different_configs() -> None:
     hash2 = CORE.config_hash
 
     assert hash1 != hash2
+
+
+def test_make_app_name_cpp_no_mac_simple() -> None:
+    """Test simple name without MAC suffix returns string literal."""
+    cpp_expr, global_decl, byte_len = make_app_name_cpp(
+        "my-device", "buf", "-", add_mac_suffix=False
+    )
+    assert cpp_expr == '"my-device"'
+    assert global_decl is None
+    assert byte_len == 9
+
+
+def test_make_app_name_cpp_no_mac_empty() -> None:
+    """Test empty name without MAC suffix."""
+    cpp_expr, global_decl, byte_len = make_app_name_cpp(
+        "", "buf", "-", add_mac_suffix=False
+    )
+    assert cpp_expr == '""'
+    assert global_decl is None
+    assert byte_len == 0
+
+
+def test_make_app_name_cpp_mac_suffix() -> None:
+    """Test name with MAC suffix emits static buffer."""
+    cpp_expr, global_decl, byte_len = make_app_name_cpp(
+        "my-device", "esphome_app_name_buf", "-", add_mac_suffix=True
+    )
+    assert cpp_expr == "esphome_app_name_buf"
+    assert global_decl is not None
+    assert "static char esphome_app_name_buf[]" in global_decl
+    assert "my-device-XXXXXX" in global_decl
+    assert byte_len == len("my-device-XXXXXX")
+
+
+def test_make_app_name_cpp_mac_suffix_empty() -> None:
+    """Test empty name with MAC suffix emits empty static buffer."""
+    cpp_expr, global_decl, byte_len = make_app_name_cpp(
+        "", "esphome_app_name_buf", "-", add_mac_suffix=True
+    )
+    assert cpp_expr == "esphome_app_name_buf"
+    assert global_decl is not None
+    assert "static char esphome_app_name_buf[]" in global_decl
+    assert byte_len == 0
+
+
+def test_make_app_name_cpp_mac_suffix_space_sep() -> None:
+    """Test friendly name uses space separator for MAC suffix."""
+    cpp_expr, global_decl, byte_len = make_app_name_cpp(
+        "My Device", "esphome_app_friendly_name_buf", " ", add_mac_suffix=True
+    )
+    assert cpp_expr == "esphome_app_friendly_name_buf"
+    assert global_decl is not None
+    assert "My Device XXXXXX" in global_decl
+    assert byte_len == len("My Device XXXXXX")
+
+
+def test_make_app_name_cpp_non_ascii_utf8_length() -> None:
+    """Test non-ASCII characters use UTF-8 byte length."""
+    _, global_decl, byte_len = make_app_name_cpp(
+        "café", "buf", "-", add_mac_suffix=False
+    )
+    assert byte_len == len("café".encode())  # 5 bytes, not 4 chars
+    assert global_decl is None
+
+
+def test_make_app_name_cpp_non_ascii_mac_suffix_utf8_length() -> None:
+    """Test non-ASCII with MAC suffix uses UTF-8 byte length."""
+    _, _, byte_len = make_app_name_cpp("café", "buf", "-", add_mac_suffix=True)
+    assert byte_len == len("café-XXXXXX".encode())
+
+
+def test_make_app_name_cpp_special_chars_escaped() -> None:
+    """Test special characters are properly escaped in C++ string."""
+    cpp_expr, _, _ = make_app_name_cpp('my "device"', "buf", "-", add_mac_suffix=False)
+    # cpp_string_escape uses octal escapes for quotes
+    assert '"' not in cpp_expr[1:-1]  # no unescaped quotes inside the outer quotes

tests/unit_tests/core/test_entity_helpers.py

@@ -23,6 +23,7 @@ from esphome.core.entity_helpers import (
     _setup_entity_impl,
     entity_duplicate_validator,
     get_base_entity_object_id,
+    register_icon,
     setup_entity,
 )
 from esphome.cpp_generator import MockObj
@@ -909,6 +910,22 @@ def test_register_string_overflow() -> None:
         _register_string("overflow", category, 3, "test")
 
 
+def test_register_icon_max_length() -> None:
+    """Test register_icon rejects icons exceeding 63 characters."""
+    # 63 chars should succeed
+    max_icon = "mdi:" + "a" * 59  # 63 total
+    idx = register_icon(max_icon)
+    assert idx > 0
+
+    # 64 chars should fail
+    too_long = "mdi:" + "a" * 60  # 64 total
+    with pytest.raises(ValueError, match="Icon string too long"):
+        register_icon(too_long)
+
+    # Empty string returns 0
+    assert register_icon("") == 0
+
+
 @pytest.mark.asyncio
 async def test_setup_entity_with_entity_category(
     setup_test_environment: list[str],

tests/unit_tests/test_config_validation.py

@@ -148,6 +148,18 @@ def test_icon__invalid():
         config_validation.icon("foo")
 
 
+def test_icon__max_length():
+    """Test that icons exceeding 63 characters are rejected."""
+    # Exactly 63 chars should pass
+    max_icon = "mdi:" + "a" * 59  # 63 chars total
+    assert config_validation.icon(max_icon) == max_icon
+
+    # 64 chars should fail
+    too_long = "mdi:" + "a" * 60  # 64 chars total
+    with pytest.raises(Invalid, match="Icon string is too long"):
+        config_validation.icon(too_long)
+
+
 @pytest.mark.parametrize("value", ("True", "YES", "on", "enAblE", True))
 def test_boolean__valid_true(value):
     assert config_validation.boolean(value) is True