Share the per-board ldscript rule via boards.board_ld_script

One source of truth for the PlatformIO pinning and the native
generator's fallback, so the per-board rule cannot drift.

esphome/components/esp8266/__init__.py

@@ -35,7 +35,7 @@ from esphome.platformio.toolchain import copy_ccache_script
 from esphome.storage_json import StorageJSON
 from esphome.types import ConfigType
 
-from .boards import BOARDS, ESP8266_LD_SCRIPTS
+from .boards import BOARDS, ESP8266_LD_SCRIPTS, board_ld_script
 from .const import (
     CONF_EARLY_PIN_INIT,
     CONF_ENABLE_SERIAL,
@@ -409,7 +409,7 @@ async def to_code(config: ConfigType) -> None:
         else:
             # A per-board override preserves a layout the board shipped
             # with (see d1_wroom_02 in boards.py)
-            ld_script = board_data.get("ldscript", ld_scripts[1])
+            ld_script = board_ld_script(board_data)
 
         if ld_script is not None:
             cg.add_platformio_option("board_build.ldscript", ld_script)

esphome/components/esp8266/boards.py

@@ -1,3 +1,5 @@
+from .const import KEY_FLASH_SIZE
+
 FLASH_SIZE_1_MB = 2**20
 FLASH_SIZE_512_KB = FLASH_SIZE_1_MB // 2
 FLASH_SIZE_2_MB = 2 * FLASH_SIZE_1_MB
@@ -182,6 +184,17 @@ for x in platform-espressif8266/boards/*.json; do
 done | sort
 """
 
+
+def board_ld_script(board_data: dict) -> str:
+    """The modern (core > 2.4.2) flash linker script for a board: its
+    shipped-layout override, else the size default (the no-FS layout).
+
+    Single source of truth for the PlatformIO pinning in __init__ and the
+    native generator's fallback, so the per-board rule cannot drift.
+    """
+    return board_data.get("ldscript", ESP8266_LD_SCRIPTS[board_data[KEY_FLASH_SIZE]][1])
+
+
 BOARDS = {
     "agruminolemon": {
         "name": "Lifely Agrumino Lemon v4",