[rp2040] Always show BOOTSEL tip when no BOOTSEL device detected

Serial ports in the chooser may belong to other devices (e.g. FT232R),
not the RP2040. Show the BOOTSEL tip whenever no BOOTSEL device is
detected via picotool, regardless of whether serial ports are present.

tests/unit_tests/test_main.py

@@ -934,6 +934,31 @@ def test_choose_upload_log_host_rp2040_bootsel_tip_with_ota(
         assert "BOOTSEL" in caplog.text
 
 
+def test_choose_upload_log_host_rp2040_bootsel_tip_with_serial_ports(
+    caplog: pytest.LogCaptureFixture,
+    mock_choose_prompt: Mock,
+) -> None:
+    """Test BOOTSEL tip shown when serial ports exist but no BOOTSEL device."""
+    setup_core(platform=PLATFORM_RP2040)
+
+    mock_ports = [MockSerialPort("/dev/ttyACM0", "RP2040 Serial")]
+    with (
+        patch("esphome.__main__.get_serial_ports", return_value=mock_ports),
+        patch(
+            "esphome.__main__._find_picotool",
+            return_value=Path("/usr/bin/picotool"),
+        ),
+        patch("esphome.__main__.detect_rp2040_bootsel", return_value=0),
+        caplog.at_level(logging.INFO, logger="esphome.__main__"),
+    ):
+        choose_upload_log_host(
+            default=None,
+            check_default=None,
+            purpose=Purpose.UPLOADING,
+        )
+        assert "BOOTSEL" in caplog.text
+
+
 def test_choose_upload_log_host_no_bootsel_for_non_rp2040(
     mock_no_serial_ports: Mock,
 ) -> None: