From 59db01e8d7beeac650944f8bcdd14c1a9430cb33 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 28 Feb 2026 11:15:17 -1000
Subject: [PATCH] Fix IRAM_ATTR not defined on LibreTiny (bk72xx)

IRAM_ATTR is defined by esp_attr.h on ESP32 but not on LibreTiny.
Add a no-op fallback in the C file since hal.h (which defines it
for C++) cannot be included from C.
---
 esphome/core/lwip_fast_select.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/esphome/core/lwip_fast_select.c b/esphome/core/lwip_fast_select.c
index 4e7ab07125..da0f1f337a 100644
--- a/esphome/core/lwip_fast_select.c
+++ b/esphome/core/lwip_fast_select.c
@@ -126,6 +126,12 @@
 
 #include <stddef.h>
 
+// IRAM_ATTR is defined by esp_attr.h (included via FreeRTOS headers) on ESP32.
+// On LibreTiny it's not defined — provide a no-op fallback.
+#ifndef IRAM_ATTR
+#define IRAM_ATTR
+#endif
+
 // Compile-time verification of thread safety assumptions.
 // On ESP32 (Xtensa/RISC-V) and LibreTiny (ARM Cortex-M), naturally-aligned
 // reads/writes up to 32 bits are atomic.