Merge branch 'dev' into partition-table-ota

esphome/components/esphome/ota/ota_esphome.cpp

@@ -242,6 +242,7 @@ void ESPHomeOTAComponent::handle_handshake_() {
       // legacy response.
       this->extended_proto_ = (this->ota_features_ & CLIENT_FEATURE_SUPPORTS_EXTENDED_PROTOCOL) != 0;
       if (this->extended_proto_) {
+        static_assert(HANDSHAKE_BUF_SIZE >= 2, "handshake_buf_ must hold the 2-byte extended-protocol feature ack");
         this->handshake_buf_[0] = ota::OTA_RESPONSE_FEATURE_FLAGS;
         this->handshake_buf_[1] = (supports_compression ? SERVER_FEATURE_SUPPORTS_COMPRESSION : 0);
 #ifdef USE_OTA_PARTITIONS
@@ -379,6 +380,11 @@ void ESPHomeOTAComponent::handle_data_() {
              (static_cast<size_t>(buf[2]) << 8) | buf[3];
   ESP_LOGV(TAG, "Size is %u bytes", ota_size);
 
+  if (ota_type != ota::OTA_TYPE_UPDATE_APP) {
+    error_code = ota::OTA_RESPONSE_ERROR_UNSUPPORTED_OTA_TYPE;
+    goto error;  // NOLINT(cppcoreguidelines-avoid-goto)
+  }
+
   // Now that we've passed authentication and are actually
   // starting the update, set the warning status and notify
   // listeners. This ensures that port scanners do not

esphome/components/esphome/ota/ota_esphome.h

@@ -98,8 +98,9 @@ class ESPHomeOTAComponent final : public ota::OTAComponent {
   ota::OTABackendPtr backend_;
 
   uint32_t client_connect_time_{0};
+  static constexpr size_t HANDSHAKE_BUF_SIZE = 5;
   uint16_t port_;
-  uint8_t handshake_buf_[5];
+  uint8_t handshake_buf_[HANDSHAKE_BUF_SIZE];
   OTAState ota_state_{OTAState::IDLE};
   uint8_t handshake_buf_pos_{0};
   uint8_t ota_features_{0};
@@ -107,6 +108,7 @@ class ESPHomeOTAComponent final : public ota::OTAComponent {
   uint8_t auth_buf_pos_{0};
   uint8_t auth_type_{0};  // Store auth type to know which hasher to use
 #endif                    // USE_OTA_PASSWORD
+  bool extended_proto_{false};
 };
 
 }  // namespace esphome

esphome/components/usb_host/__init__.py

@@ -10,6 +10,7 @@ from esphome.components.esp32 import (
 )
 import esphome.config_validation as cv
 from esphome.const import CONF_DEVICES, CONF_ID
+from esphome.core import CORE
 from esphome.cpp_types import Component
 from esphome.types import ConfigType
 
@@ -19,14 +20,15 @@ DEPENDENCIES = ["esp32"]
 usb_host_ns = cg.esphome_ns.namespace("usb_host")
 USBHost = usb_host_ns.class_("USBHost", Component)
 USBClient = usb_host_ns.class_("USBClient", Component)
-
+DOMAIN = "usb_host"
 CONF_VID = "vid"
 CONF_PID = "pid"
 CONF_ENABLE_HUBS = "enable_hubs"
 CONF_MAX_TRANSFER_REQUESTS = "max_transfer_requests"
+CONF_MAX_PACKET_SIZE = "max_packet_size"
 
 
-def usb_device_schema(cls=USBClient, vid: int = None, pid: [int] = None) -> cv.Schema:
+def usb_device_schema(cls=USBClient, vid: int = None, pid: int = None) -> cv.Schema:
     schema = cv.COMPONENT_SCHEMA.extend(
         {
             cv.GenerateID(): cv.declare_id(cls),
@@ -43,6 +45,17 @@ def usb_device_schema(cls=USBClient, vid: int = None, pid: [int] = None) -> cv.S
     return schema
 
 
+def _set_max_packet_size(config: dict) -> dict:
+    CORE.data.setdefault(DOMAIN, {})[CONF_MAX_PACKET_SIZE] = config[
+        CONF_MAX_PACKET_SIZE
+    ]
+    return config
+
+
+def get_max_packet_size() -> int:
+    return CORE.data.get(DOMAIN, {}).get(CONF_MAX_PACKET_SIZE, 64)
+
+
 CONFIG_SCHEMA = cv.All(
     cv.COMPONENT_SCHEMA.extend(
         {
@@ -51,10 +64,14 @@ CONFIG_SCHEMA = cv.All(
             cv.Optional(CONF_MAX_TRANSFER_REQUESTS, default=16): cv.int_range(
                 min=1, max=32
             ),
+            cv.Optional(CONF_MAX_PACKET_SIZE, default=64): cv.one_of(
+                64, 128, 256, 512, 1024, int=True
+            ),
             cv.Optional(CONF_DEVICES): cv.ensure_list(usb_device_schema()),
         }
     ),
     only_on_variant(supported=[VARIANT_ESP32P4, VARIANT_ESP32S2, VARIANT_ESP32S3]),
+    _set_max_packet_size,
 )
 
 
@@ -72,8 +89,8 @@ async def to_code(config: ConfigType) -> None:
     if config.get(CONF_ENABLE_HUBS):
         add_idf_sdkconfig_option("CONFIG_USB_HOST_HUBS_SUPPORTED", True)
 
-    max_requests = config[CONF_MAX_TRANSFER_REQUESTS]
-    cg.add_define("USB_HOST_MAX_REQUESTS", max_requests)
+    cg.add_define("USB_HOST_MAX_REQUESTS", config[CONF_MAX_TRANSFER_REQUESTS])
+    cg.add_define("USB_HOST_MAX_PACKET_SIZE", config[CONF_MAX_PACKET_SIZE])
 
     var = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(var, config)

esphome/components/usb_host/usb_host.h

@@ -66,6 +66,8 @@ static_assert(MAX_REQUESTS >= 1 && MAX_REQUESTS <= 32, "MAX_REQUESTS must be bet
 using trq_bitmask_t = std::conditional<(MAX_REQUESTS <= 16), uint16_t, uint32_t>::type;
 static constexpr trq_bitmask_t ALL_REQUESTS_IN_USE = MAX_REQUESTS == 32 ? ~0 : (1 << MAX_REQUESTS) - 1;
 
+static constexpr size_t USB_MAX_PACKET_SIZE =
+    USB_HOST_MAX_PACKET_SIZE;                        // Max USB packet size (64 for FS, 512 for P4 HS)
 static constexpr size_t USB_EVENT_QUEUE_SIZE = 32;   // Size of event queue between USB task and main loop
 static constexpr size_t USB_TASK_STACK_SIZE = 4096;  // Stack size for USB task (same as ESP-IDF USB examples)
 static constexpr UBaseType_t USB_TASK_PRIORITY = 5;  // Higher priority than main loop (tskIDLE_PRIORITY + 5)

esphome/components/usb_host/usb_host_client.cpp

@@ -217,7 +217,7 @@ void USBClient::setup() {
   // Pre-allocate USB transfer buffers for all slots at startup
   // This avoids any dynamic allocation during runtime
   for (auto &request : this->requests_) {
-    usb_host_transfer_alloc(64, 0, &request.transfer);
+    usb_host_transfer_alloc(USB_MAX_PACKET_SIZE, 0, &request.transfer);
     request.client = this;  // Set once, never changes
   }
 

esphome/components/usb_uart/__init__.py

@@ -1,7 +1,11 @@
 import esphome.codegen as cg
 from esphome.components.const import CONF_DATA_BITS, CONF_PARITY, CONF_STOP_BITS
 from esphome.components.uart import CONF_DEBUG_PREFIX, CONF_FLUSH_TIMEOUT, UARTComponent
-from esphome.components.usb_host import register_usb_client, usb_device_schema
+from esphome.components.usb_host import (
+    get_max_packet_size,
+    register_usb_client,
+    usb_device_schema,
+)
 import esphome.config_validation as cv
 from esphome.const import (
     CONF_BAUD_RATE,
@@ -118,14 +122,14 @@ CONFIG_SCHEMA = cv.ensure_list(
 async def to_code(config):
     # The output chunk pool/queue are compile-time-sized templates shared by all
     # USBUartChannel instances, so use the largest buffer_size across every channel
-    # of every device.  Each chunk is 64 bytes (USB FS MPS); add one extra slot
-    # because LockFreeQueue<T,N> is a ring buffer that wastes one entry.
+    # of every device. Add one extra slot because LockFreeQueue<T,N> is a ring
+    # buffer that wastes one entry.
     max_buffer_size = max(
         channel[CONF_BUFFER_SIZE]
         for device in config
         for channel in device[CONF_CHANNELS]
     )
-    output_chunk_count = max_buffer_size // 64 + 1
+    output_chunk_count = max(max_buffer_size // get_max_packet_size(), 2) + 1
     cg.add_define("USB_UART_OUTPUT_CHUNK_COUNT", output_chunk_count)
 
     for device in config:

esphome/components/usb_uart/usb_uart.cpp

@@ -157,7 +157,7 @@ void USBUartChannel::write_array(const uint8_t *data, size_t len) {
       ESP_LOGE(TAG, "Output pool full - lost %zu bytes", len);
       break;
     }
-    size_t chunk_len = std::min(len, UsbOutputChunk::MAX_CHUNK_SIZE);
+    uint16_t chunk_len = std::min(len, UsbOutputChunk::MAX_CHUNK_SIZE);
     memcpy(chunk->data, data, chunk_len);
     chunk->length = static_cast<uint8_t>(chunk_len);
     // Push always succeeds: pool is sized to queue capacity (SIZE-1), so if
@@ -222,7 +222,7 @@ void USBUartComponent::loop() {
 
 #ifdef USE_UART_DEBUGGER
     if (channel->debug_) {
-      char buf[4 + format_hex_pretty_size(UsbDataChunk::MAX_CHUNK_SIZE)];  // "<<< " + hex
+      char buf[4 + format_hex_pretty_size(usb_host::USB_MAX_PACKET_SIZE)];  // "<<< " + hex
       memcpy(buf, "<<< ", 4);
       format_hex_pretty_to(buf + 4, sizeof(buf) - 4, chunk->data, chunk->length, ',');
       ESP_LOGD(TAG, "%s%s", channel->debug_prefix_.c_str(), buf);
@@ -377,7 +377,7 @@ void USBUartComponent::start_output(USBUartChannel *channel) {
     this->start_output(channel);
   };
 
-  const uint8_t len = chunk->length;
+  const auto len = chunk->length;
   if (!this->transfer_out(ep->bEndpointAddress, callback, chunk->data, len)) {
     // Transfer submission failed — return chunk and release flag so callers can retry.
     channel->output_pool_.release(chunk);
@@ -394,10 +394,10 @@ void USBUartComponent::start_output(USBUartChannel *channel) {
 static void fix_mps(const usb_ep_desc_t *ep) {
   if (ep != nullptr) {
     auto *ep_mutable = const_cast<usb_ep_desc_t *>(ep);
-    if (ep->wMaxPacketSize > 64) {
-      ESP_LOGW(TAG, "Corrected MPS of EP 0x%02X from %u to 64", static_cast<uint8_t>(ep->bEndpointAddress & 0xFF),
-               ep->wMaxPacketSize);
-      ep_mutable->wMaxPacketSize = 64;
+    if (ep->wMaxPacketSize > usb_host::USB_MAX_PACKET_SIZE) {
+      ESP_LOGW(TAG, "Corrected MPS of EP 0x%02X from %u to %u", static_cast<uint8_t>(ep->bEndpointAddress & 0xFF),
+               ep->wMaxPacketSize, usb_host::USB_MAX_PACKET_SIZE);
+      ep_mutable->wMaxPacketSize = usb_host::USB_MAX_PACKET_SIZE;
     }
   }
 }

esphome/components/usb_uart/usb_uart.h

@@ -106,20 +106,19 @@ class RingBuffer {
 
 // Structure for queuing received USB data chunks
 struct UsbDataChunk {
-  static constexpr size_t MAX_CHUNK_SIZE = 64;  // USB packet size
-  uint8_t data[MAX_CHUNK_SIZE];
-  uint8_t length;  // Max 64 bytes, so uint8_t is sufficient
+  uint8_t data[usb_host::USB_MAX_PACKET_SIZE];
+  uint16_t length;
   USBUartChannel *channel;
 
   // Required for EventPool - no cleanup needed for POD types
   void release() {}
 };
 
-// Structure for queuing outgoing USB data chunks (one per USB FS packet)
+// Structure for queuing outgoing USB data chunks (one per USB packet)
 struct UsbOutputChunk {
-  static constexpr size_t MAX_CHUNK_SIZE = 64;  // USB FS MPS
+  static constexpr size_t MAX_CHUNK_SIZE = usb_host::USB_MAX_PACKET_SIZE;
   uint8_t data[MAX_CHUNK_SIZE];
-  uint8_t length;
+  uint16_t length;
 
   // Required for EventPool - no cleanup needed for POD types
   void release() {}

esphome/core/ring_buffer.cpp

@@ -1,11 +1,9 @@
 #include "ring_buffer.h"
 
-#include "esphome/core/helpers.h"
-#include "esphome/core/log.h"
-
 #ifdef USE_ESP32
 
-#include "helpers.h"
+#include "esphome/core/helpers.h"
+#include "esphome/core/log.h"
 
 namespace esphome {
 
@@ -19,12 +17,15 @@ RingBuffer::~RingBuffer() {
   }
 }
 
-std::unique_ptr<RingBuffer> RingBuffer::create(size_t len) {
+std::unique_ptr<RingBuffer> RingBuffer::create(size_t len, MemoryPreference preference) {
   std::unique_ptr<RingBuffer> rb = make_unique<RingBuffer>();
 
   rb->size_ = len;
 
-  RAMAllocator<uint8_t> allocator;
+  const uint8_t type = (preference == MemoryPreference::INTERNAL_FIRST) ? RAMAllocator<uint8_t>::PREFER_INTERNAL
+                                                                        : RAMAllocator<uint8_t>::NONE;
+
+  RAMAllocator<uint8_t> allocator(type);
   rb->storage_ = allocator.allocate(rb->size_);
   if (rb->storage_ == nullptr) {
     return nullptr;

esphome/core/ring_buffer.h

@@ -80,7 +80,12 @@ class RingBuffer {
    */
   BaseType_t reset();
 
-  static std::unique_ptr<RingBuffer> create(size_t len);
+  enum class MemoryPreference {
+    EXTERNAL_FIRST,  // External RAM preferred, fall back to internal (default)
+    INTERNAL_FIRST,  // Internal RAM preferred, fall back to external
+  };
+
+  static std::unique_ptr<RingBuffer> create(size_t len, MemoryPreference preference = MemoryPreference::EXTERNAL_FIRST);
 
  protected:
   /// @brief Discards data from the ring buffer.

esphome/espota2.py

@@ -62,6 +62,11 @@ CLIENT_FEATURE_SUPPORTS_EXTENDED_PROTOCOL = 0x04
 SERVER_FEATURE_SUPPORTS_COMPRESSION = 0x01
 SERVER_FEATURE_SUPPORTS_PARTITION_ACCESS = 0x02
 
+# OTA types this client knows how to send. Future PRs that add bootloader/partition
+# updates extend this set. Anything outside the set is rejected up front so callers
+# of perform_ota/run_ota get a clear error instead of a post-auth 0x8E from the device.
+_SUPPORTED_OTA_TYPES: frozenset[int] = frozenset({OTA_TYPE_UPDATE_APP})
+
 UPLOAD_BLOCK_SIZE = 8192
 UPLOAD_BUFFER_SIZE = UPLOAD_BLOCK_SIZE * 8
 
@@ -204,8 +209,10 @@ def check_error(data: list[int] | bytes, expect: int | list[int] | None) -> None
     :param expect: Expected response code(s), None to skip validation.
     :raises OTAError: If an error code is detected or response doesn't match expected.
     """
-    if expect is None:
-        return
+    # Detect device errors and connection-closed cases regardless of `expect`. If we
+    # only ran these checks when expect was set, error bytes returned during
+    # accept-any-response reads (e.g. feature negotiation, auth nonces) would be
+    # silently passed through and surface later as cryptic decode/timeout failures.
     if not data:
         raise OTAError(
             "Error: Device closed connection without responding. "
@@ -216,6 +223,8 @@ def check_error(data: list[int] | bytes, expect: int | list[int] | None) -> None
     error_msg = _ERROR_MESSAGES.get(dat)
     if error_msg is not None:
         raise OTAError(f"Error: {error_msg}")
+    if expect is None:
+        return
     if not isinstance(expect, (list, tuple)):
         expect = [expect]
     if dat not in expect:
@@ -252,6 +261,19 @@ def perform_ota(
     filename: Path,
     ota_type: int = OTA_TYPE_UPDATE_APP,
 ) -> None:
+    # Validate ota_type up front. It travels as a single byte on the wire, and
+    # passing an out-of-range value would only surface as a ValueError from
+    # bytes([ota_type]) deep inside send_check, bypassing OTAError handling.
+    if not isinstance(ota_type, int) or not 0 <= ota_type <= 0xFF:
+        raise OTAError(
+            f"Invalid ota_type {ota_type!r}; expected an integer in range 0-255"
+        )
+    if ota_type not in _SUPPORTED_OTA_TYPES:
+        supported = ", ".join(f"0x{t:02X}" for t in sorted(_SUPPORTED_OTA_TYPES))
+        raise OTAError(
+            f"Unsupported OTA type 0x{ota_type:02X}; this ESPHome supports: {supported}"
+        )
+
     file_contents = file_handle.read()
     file_size = len(file_contents)
     _LOGGER.info("Uploading %s (%s bytes)", filename, file_size)
@@ -296,14 +318,20 @@ def perform_ota(
     else:
         features = 0
 
-    if ota_type not in (OTA_TYPE_UPDATE_APP, OTA_TYPE_UPDATE_PARTITION_TABLE):
-        raise OTAError(f"Unsupported OTA type: 0x{ota_type:02X}")
-
-    if (
-        ota_type != OTA_TYPE_UPDATE_APP
-        and not features & SERVER_FEATURE_SUPPORTS_PARTITION_ACCESS
-    ):
-        raise OTAError("Device only supports app updates")
+    if ota_type != OTA_TYPE_UPDATE_APP:
+        # Any non-app OTA type requires the extended protocol and the
+        # partition-access server feature. Reject up front so the user gets
+        # a clear capability error instead of a post-auth 0x8E from the device.
+        if not extended_proto:
+            raise OTAError(
+                f"Device does not support extended OTA protocol; "
+                f"OTA type 0x{ota_type:02X} requires it"
+            )
+        if not (features & SERVER_FEATURE_SUPPORTS_PARTITION_ACCESS):
+            raise OTAError(
+                f"Device does not support partition access; "
+                f"OTA type 0x{ota_type:02X} cannot be used"
+            )
 
     if features & SERVER_FEATURE_SUPPORTS_COMPRESSION:
         upload_contents = gzip.compress(file_contents, compresslevel=9)

tests/unit_tests/test_espota2.py

@@ -786,6 +786,59 @@ def test_perform_ota_version_differences(
     assert mock_socket.recv.call_count == 9  # v2.0 has 9 recv calls (includes chunk OK)
 
 
+@pytest.mark.usefixtures("mock_time")
+def test_perform_ota_extended_protocol_app(
+    mock_socket: Mock, mock_file: io.BytesIO
+) -> None:
+    """Test OTA extended protocol app update."""
+    recv_responses = [
+        bytes([espota2.RESPONSE_OK]),  # First byte of version response
+        bytes([espota2.OTA_VERSION_2_0]),  # Version number
+        bytes([espota2.RESPONSE_FEATURE_FLAGS]),  # Device supports extended protocol
+        bytes(
+            [
+                espota2.SERVER_FEATURE_SUPPORTS_COMPRESSION
+                | espota2.SERVER_FEATURE_SUPPORTS_PARTITION_ACCESS
+            ]
+        ),  # Device feature flags
+        bytes([espota2.RESPONSE_AUTH_OK]),  # No auth required
+        bytes([espota2.RESPONSE_UPDATE_PREPARE_OK]),  # Binary size OK
+        bytes([espota2.RESPONSE_BIN_MD5_OK]),  # MD5 checksum OK
+        bytes([espota2.RESPONSE_CHUNK_OK]),  # Chunk OK
+        bytes([espota2.RESPONSE_RECEIVE_OK]),  # Receive OK
+        bytes([espota2.RESPONSE_UPDATE_END_OK]),  # Update end OK
+    ]
+
+    mock_socket.recv.side_effect = recv_responses
+
+    espota2.perform_ota(
+        mock_socket,
+        "testpass",
+        mock_file,
+        "test.bin",
+        espota2.OTA_TYPE_UPDATE_APP,
+    )
+
+    # Verify magic bytes were sent
+    assert mock_socket.sendall.call_args_list[0] == call(bytes(espota2.MAGIC_BYTES))
+
+    # Verify features were sent (compression + SHA256 support + extended protocol)
+    assert mock_socket.sendall.call_args_list[1] == call(
+        bytes(
+            [
+                espota2.CLIENT_FEATURE_SUPPORTS_COMPRESSION
+                | espota2.CLIENT_FEATURE_SUPPORTS_SHA256_AUTH
+                | espota2.CLIENT_FEATURE_SUPPORTS_EXTENDED_PROTOCOL
+            ]
+        )
+    )
+
+    # Verify ota type was sent
+    assert mock_socket.sendall.call_args_list[2] == call(
+        bytes([espota2.OTA_TYPE_UPDATE_APP])
+    )
+
+
 @pytest.mark.usefixtures("mock_time")
 def test_perform_ota_successful_partition_table(
     mock_socket: Mock, mock_file: io.BytesIO
@@ -861,3 +914,167 @@ def test_perform_ota_extended_protocol_unsupported(
             "partitions.bin",
             espota2.OTA_TYPE_UPDATE_PARTITION_TABLE,
         )
+
+
+@pytest.mark.usefixtures("mock_time")
+def test_perform_ota_device_rejects_with_unsupported_ota_type(
+    mock_socket: Mock, mock_file: io.BytesIO
+) -> None:
+    """End-to-end: device returns 0x8E after the size byte; perform_ota must
+    surface the human-readable 'unsupported OTA type' error from the lookup
+    table in check_error()."""
+    recv_responses = [
+        bytes([espota2.RESPONSE_OK]),  # First byte of version response
+        bytes([espota2.OTA_VERSION_2_0]),  # Version number
+        bytes([espota2.RESPONSE_FEATURE_FLAGS]),  # Extended protocol marker
+        bytes(
+            [
+                espota2.SERVER_FEATURE_SUPPORTS_COMPRESSION
+                | espota2.SERVER_FEATURE_SUPPORTS_PARTITION_ACCESS
+            ]
+        ),  # Feature flags
+        bytes([espota2.RESPONSE_AUTH_OK]),  # No auth required
+        bytes([espota2.RESPONSE_ERROR_UNSUPPORTED_OTA_TYPE]),  # Reject at size step
+    ]
+
+    mock_socket.recv.side_effect = recv_responses
+
+    with pytest.raises(
+        espota2.OTAError,
+        match="The requested OTA type is not supported by the device",
+    ):
+        espota2.perform_ota(
+            mock_socket,
+            "testpass",
+            mock_file,
+            "test.bin",
+            espota2.OTA_TYPE_UPDATE_APP,
+        )
+
+    # Verify the client did send the OTA type byte before the size step
+    assert mock_socket.sendall.call_args_list[2] == call(
+        bytes([espota2.OTA_TYPE_UPDATE_APP])
+    )
+
+
+@pytest.mark.usefixtures("mock_time")
+def test_perform_ota_unsupported_type_rejected_early(
+    mock_socket: Mock, mock_file: io.BytesIO
+) -> None:
+    """ota_type values not in _SUPPORTED_OTA_TYPES are rejected before any I/O."""
+    with pytest.raises(espota2.OTAError, match="Unsupported OTA type 0xFF"):
+        espota2.perform_ota(
+            mock_socket,
+            "testpass",
+            mock_file,
+            "test.bin",
+            0xFF,
+        )
+    # No bytes should have been transmitted to the device.
+    mock_socket.sendall.assert_not_called()
+
+
+@pytest.mark.parametrize("bad_type", [-1, 256, 0x10000, "app", None, 1.5])
+def test_perform_ota_rejects_out_of_range_type(
+    mock_socket: Mock, mock_file: io.BytesIO, bad_type: object
+) -> None:
+    """Out-of-range or non-int ota_type must raise OTAError, not ValueError."""
+    with pytest.raises(espota2.OTAError, match="Invalid ota_type"):
+        espota2.perform_ota(
+            mock_socket,
+            "testpass",
+            mock_file,
+            "test.bin",
+            bad_type,  # type: ignore[arg-type]
+        )
+    mock_socket.sendall.assert_not_called()
+
+
+@pytest.mark.usefixtures("mock_time")
+def test_perform_ota_non_app_type_requires_extended_protocol(
+    mock_socket: Mock, mock_file: io.BytesIO, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Non-app OTA type must fail when device only supports the legacy protocol."""
+    monkeypatch.setattr(
+        espota2,
+        "_SUPPORTED_OTA_TYPES",
+        frozenset({espota2.OTA_TYPE_UPDATE_APP, 0xFF}),
+    )
+    recv_responses = [
+        bytes([espota2.RESPONSE_OK]),  # First byte of version response
+        bytes([espota2.OTA_VERSION_2_0]),  # Version number
+        bytes([espota2.RESPONSE_HEADER_OK]),  # Legacy single-byte feature ack
+    ]
+
+    mock_socket.recv.side_effect = recv_responses
+
+    with pytest.raises(
+        espota2.OTAError, match="Device does not support extended OTA protocol"
+    ):
+        espota2.perform_ota(
+            mock_socket,
+            "testpass",
+            mock_file,
+            "test.bin",
+            0xFF,
+        )
+
+
+@pytest.mark.usefixtures("mock_time")
+def test_perform_ota_non_app_type_requires_partition_access(
+    mock_socket: Mock, mock_file: io.BytesIO, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Non-app OTA type must fail when device advertises extended protocol but
+    not the partition-access feature."""
+    monkeypatch.setattr(
+        espota2,
+        "_SUPPORTED_OTA_TYPES",
+        frozenset({espota2.OTA_TYPE_UPDATE_APP, 0xFF}),
+    )
+    recv_responses = [
+        bytes([espota2.RESPONSE_OK]),  # First byte of version response
+        bytes([espota2.OTA_VERSION_2_0]),  # Version number
+        bytes([espota2.RESPONSE_FEATURE_FLAGS]),  # Extended protocol marker
+        bytes(
+            [espota2.SERVER_FEATURE_SUPPORTS_COMPRESSION]
+        ),  # Compression only, no partition access
+    ]
+
+    mock_socket.recv.side_effect = recv_responses
+
+    with pytest.raises(
+        espota2.OTAError, match="Device does not support partition access"
+    ):
+        espota2.perform_ota(
+            mock_socket,
+            "testpass",
+            mock_file,
+            "test.bin",
+            0xFF,
+        )
+
+
+def test_check_error_detects_errors_when_expect_is_none() -> None:
+    """check_error must surface device error bytes even when expect is None.
+
+    Regression test: previously, receive_exactly(..., expect=None) calls (used
+    during feature negotiation and nonce reads) silently passed error bytes
+    through, turning clean device errors into confusing later failures.
+    """
+    with pytest.raises(espota2.OTAError, match="Error: Authentication invalid"):
+        espota2.check_error([espota2.RESPONSE_ERROR_AUTH_INVALID], None)
+
+
+def test_check_error_detects_empty_when_expect_is_none() -> None:
+    """Empty data with expect=None must still raise (connection closed)."""
+    with pytest.raises(
+        espota2.OTAError, match="Device closed connection without responding"
+    ):
+        espota2.check_error([], None)
+
+
+def test_check_error_passes_non_error_when_expect_is_none() -> None:
+    """Non-error bytes with expect=None must pass through silently."""
+    espota2.check_error([espota2.RESPONSE_OK], None)
+    espota2.check_error([espota2.RESPONSE_HEADER_OK], None)
+    espota2.check_error([espota2.RESPONSE_FEATURE_FLAGS], None)