[rp2040] Fix firmware.bin.signed creation for nobuild upload

Move signed bin creation from post_build script to upload_using_platformio.
The post_build AddPostAction only runs during build, not during nobuild
upload, so the file was missing when PlatformIO tried to upload.
Now create firmware.bin.signed before calling PlatformIO upload.

esphome/__main__.py

@@ -736,8 +736,21 @@ def upload_using_esptool(
 
 
 def upload_using_platformio(config: ConfigType, port: str) -> int:
+    import shutil
+
     from esphome import platformio_api
 
+    # RP2040 platform-raspberrypi build recipe expects firmware.bin.signed for
+    # the upload target, but 'nobuild' skips the build phase that creates it.
+    # Create it here so the upload doesn't fail.
+    if CORE.data.get(KEY_CORE, {}).get(KEY_TARGET_PLATFORM) == PLATFORM_RP2040:
+        idedata = platformio_api.get_idedata(config)
+        build_dir = Path(idedata.firmware_elf_path).parent
+        firmware_bin = build_dir / "firmware.bin"
+        signed_bin = build_dir / "firmware.bin.signed"
+        if firmware_bin.is_file() and not signed_bin.is_file():
+            shutil.copy2(firmware_bin, signed_bin)
+
     upload_args = ["-t", "upload", "-t", "nobuild"]
     if port is not None:
         upload_args += ["--upload-port", port]

esphome/components/rp2040/post_build.py.script

@@ -18,21 +18,6 @@ def rp2040_copy_ota_bin(source, target, env):
     shutil.copyfile(firmware_name, new_file_name)
 
 
-def rp2040_copy_signed_bin(source, target, env):
-    """Create firmware.bin.signed so that 'nobuild' upload target can find it.
-
-    The platform-raspberrypi build recipe creates firmware.bin.signed as a build
-    target, but the 'nobuild' upload flag skips the build phase. Without this
-    file, the upload fails with 'firmware.bin.signed not found'.
-    ESPHome does not use signing for RP2040, so this is just a copy.
-    """
-    firmware_name = env.subst("$BUILD_DIR/${PROGNAME}.bin")
-    signed_name = env.subst("$BUILD_DIR/${PROGNAME}.bin.signed")
-
-    shutil.copyfile(firmware_name, signed_name)
-
-
 # pylint: disable=E0602
 env.AddPostAction("$BUILD_DIR/${PROGNAME}.bin", rp2040_copy_factory_uf2)  # noqa
 env.AddPostAction("$BUILD_DIR/${PROGNAME}.bin", rp2040_copy_ota_bin)  # noqa
-env.AddPostAction("$BUILD_DIR/${PROGNAME}.bin", rp2040_copy_signed_bin)  # noqa

tests/unit_tests/test_main.py

@@ -40,6 +40,7 @@ from esphome.__main__ import (
     show_logs,
     upload_program,
     upload_using_esptool,
+    upload_using_platformio,
     upload_using_uf2_copy,
 )
 from esphome.components.esp32 import KEY_ESP32, KEY_VARIANT, VARIANT_ESP32
@@ -1203,6 +1204,46 @@ def test_upload_program_serial_platformio_platforms(
     mock_upload_using_platformio.assert_called_once_with(config, device)
 
 
+def test_upload_using_platformio_creates_signed_bin_for_rp2040(
+    tmp_path: Path,
+) -> None:
+    """Test that upload_using_platformio creates firmware.bin.signed for RP2040."""
+    setup_core(platform=PLATFORM_RP2040)
+
+    build_dir = tmp_path / "build"
+    build_dir.mkdir()
+    firmware_bin = build_dir / "firmware.bin"
+    firmware_bin.write_bytes(b"test firmware content")
+    firmware_elf = build_dir / "firmware.elf"
+    firmware_elf.write_bytes(b"elf")
+
+    mock_idedata = MagicMock()
+    mock_idedata.firmware_elf_path = str(firmware_elf)
+
+    with (
+        patch("esphome.platformio_api.get_idedata", return_value=mock_idedata),
+        patch("esphome.platformio_api.run_platformio_cli_run", return_value=0),
+    ):
+        result = upload_using_platformio({}, "/dev/ttyACM0")
+
+    assert result == 0
+    signed_bin = build_dir / "firmware.bin.signed"
+    assert signed_bin.is_file()
+    assert signed_bin.read_bytes() == b"test firmware content"
+
+
+def test_upload_using_platformio_skips_signed_bin_for_non_rp2040(
+    tmp_path: Path,
+) -> None:
+    """Test that upload_using_platformio doesn't create signed bin for non-RP2040."""
+    setup_core(platform=PLATFORM_ESP32)
+
+    with patch("esphome.platformio_api.run_platformio_cli_run", return_value=0):
+        result = upload_using_platformio({}, "/dev/ttyUSB0")
+
+    assert result == 0
+
+
 def test_upload_program_serial_upload_failed(
     mock_upload_using_esptool: Mock,
     mock_get_port_type: Mock,