[esphome] Skip missing extra flash images in upload_using_esptool

PlatformIO's idedata may list flash images that do not exist on disk
(e.g. a tasmota tinyuf2.bin referenced by the adafruit_qtpy_esp32s3_n4r2
board). Previously the CLI passed every entry straight to esptool, which
aborted the entire flash with "No such file or directory". The dashboard
path is unaffected because it flashes the pre-merged firmware.factory.bin
produced by the post-build step, which already tolerates missing inputs.

Filter non-existent extra_flash_images with a warning so a stale or
incorrect platform-declared image no longer breaks esphome run.

Fixes https://github.com/esphome/esphome/issues/15634

esphome/__main__.py

@@ -750,8 +750,15 @@ def upload_using_esptool(
             platformio_api.FlashImage(
                 path=idedata.firmware_bin_path, offset=firmware_offset
             ),
-            *idedata.extra_flash_images,
         ]
+        for image in idedata.extra_flash_images:
+            if not Path(image.path).is_file():
+                _LOGGER.warning(
+                    "Skipping missing flash image declared by platform: %s",
+                    image.path,
+                )
+                continue
+            flash_images.append(image)
 
     mcu = "esp8266"
     if CORE.is_esp32:

tests/unit_tests/test_main.py

@@ -1231,6 +1231,48 @@ def test_upload_using_esptool_path_conversion(
     assert partitions_path.endswith("partitions.bin")
 
 
+def test_upload_using_esptool_skips_missing_extra_flash_images(
+    tmp_path: Path,
+    mock_run_external_command_main: Mock,
+    mock_get_idedata: Mock,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """A non-existent path in extra_flash_images must be filtered out with a
+    warning, and must not appear in the esptool command line. Only the valid
+    images are flashed. Regression test for
+    https://github.com/esphome/esphome/issues/15634.
+    """
+    setup_core(platform=PLATFORM_ESP32, tmp_path=tmp_path, name="test")
+    CORE.data[KEY_ESP32] = {KEY_VARIANT: VARIANT_ESP32}
+
+    missing_path = tmp_path / "variants" / "tasmota" / "tinyuf2.bin"
+
+    mock_idedata = MagicMock(spec=platformio_api.IDEData)
+    mock_idedata.firmware_bin_path = tmp_path / "firmware.bin"
+    mock_idedata.extra_flash_images = [
+        platformio_api.FlashImage(path=tmp_path / "bootloader.bin", offset="0x1000"),
+        platformio_api.FlashImage(path=missing_path, offset="0x2d0000"),
+    ]
+    mock_get_idedata.return_value = mock_idedata
+
+    (tmp_path / "firmware.bin").touch()
+    (tmp_path / "bootloader.bin").touch()
+    # Intentionally do NOT create missing_path
+
+    config = {CONF_ESPHOME: {"platformio_options": {}}}
+
+    with caplog.at_level(logging.WARNING):
+        result = upload_using_esptool(config, "/dev/ttyUSB0", None, None)
+
+    assert result == 0
+    assert "Skipping missing flash image" in caplog.text
+    assert str(missing_path) in caplog.text
+
+    cmd_list = list(mock_run_external_command_main.call_args[0][1:])
+    assert str(missing_path) not in cmd_list
+    assert "0x2d0000" not in cmd_list
+
+
 def test_upload_using_esptool_with_file_path(
     tmp_path: Path,
     mock_run_external_command_main: Mock,