From e2b6efd8dec8fd4be9391857a77ae4cc04817099 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Thu, 4 Sep 2025 22:28:42 -0500
Subject: [PATCH] [api] Store Noise protocol prologue in flash on ESP8266

---
 esphome/components/api/api_frame_helper_noise.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/esphome/components/api/api_frame_helper_noise.cpp b/esphome/components/api/api_frame_helper_noise.cpp
index 35d1715931..37aba7ec13 100644
--- a/esphome/components/api/api_frame_helper_noise.cpp
+++ b/esphome/components/api/api_frame_helper_noise.cpp
@@ -10,10 +10,18 @@
 #include <cstring>
 #include <cinttypes>
 
+#ifdef USE_ESP8266
+#include <pgmspace.h>
+#endif
+
 namespace esphome::api {
 
 static const char *const TAG = "api.noise";
+#ifdef USE_ESP8266
+static const char PROLOGUE_INIT[] PROGMEM = "NoiseAPIInit";
+#else
 static const char *const PROLOGUE_INIT = "NoiseAPIInit";
+#endif
 static constexpr size_t PROLOGUE_INIT_LEN = 12;  // strlen("NoiseAPIInit")
 
 #define HELPER_LOG(msg, ...) ESP_LOGVV(TAG, "%s: " msg, this->client_info_->get_combined_info().c_str(), ##__VA_ARGS__)
@@ -75,7 +83,11 @@ APIError APINoiseFrameHelper::init() {
   // init prologue
   size_t old_size = prologue_.size();
   prologue_.resize(old_size + PROLOGUE_INIT_LEN);
+#ifdef USE_ESP8266
+  memcpy_P(prologue_.data() + old_size, PROLOGUE_INIT, PROLOGUE_INIT_LEN);
+#else
   std::memcpy(prologue_.data() + old_size, PROLOGUE_INIT, PROLOGUE_INIT_LEN);
+#endif
 
   state_ = State::CLIENT_HELLO;
   return APIError::OK;