Fix firmware flash stream crashes and port contention.

Expose MeshCore USB source.connected for the release gate, always stop a
matched source before esptool (reconnect loops still hold the port), and
wait longer after flash before reconnecting.

Co-Authored-By: Albert Einstein <javastraat@hotmail.com>

Author: KMX415

src/api/routes/meshcore_firmware_routes.py

@@ -312,12 +312,17 @@ async def body() -> AsyncIterator[bytes]:
                 "text": f"Using MeshCore {fw['tag']} ({fw['flavor']}).",
             })
 
-            released = source is not None and source.connected
+            # Always stop a matched source before esptool — even when
+            # handshake failed, background reconnect still races the port.
+            released = source is not None
             if released:
                 yield _ndjson({
                     "type": "line",
                     "stream": "stdout",
-                    "text": f"Releasing {port} ({source.name} was connected)…",
+                    "text": (
+                        f"Releasing {port} ({source.name}"
+                        f"{'' if source.connected else ' reconnect loop'})…"
+                    ),
                 })
                 await source.stop()
 
@@ -350,7 +355,8 @@ async def body() -> AsyncIterator[bytes]:
                         "stream": "stdout",
                         "text": "Waiting for the board to finish rebooting…",
                     })
-                    await asyncio.sleep(3.0)
+                    # ESP32-S3 USB companions often need >3s after flash.
+                    await asyncio.sleep(10.0)
                     await source.start()
                     yield _ndjson({
                         "type": "line",

src/api/routes/meshtastic_firmware_routes.py

@@ -330,12 +330,17 @@ async def body() -> AsyncIterator[bytes]:
                 "text": f"Using Meshtastic {fw['version']} ({fw['mcu']}).",
             })
 
-            released = source is not None and source.connected
+            # Always stop a matched source before esptool — reconnect /
+            # half-open serial still races the port when connected=False.
+            released = source is not None
             if released:
                 yield _ndjson({
                     "type": "line",
                     "stream": "stdout",
-                    "text": f"Releasing {port} ({source.name} was connected)…",
+                    "text": (
+                        f"Releasing {port} ({source.name}"
+                        f"{'' if source.connected else ' reconnect loop'})…"
+                    ),
                 })
                 await source.stop()
 

src/capture/meshcore_usb_source.py

@@ -71,6 +71,11 @@ def __init__(
     def name(self) -> str:
         return "meshcore_usb"
 
+    @property
+    def connected(self) -> bool:
+        """True while the MeshCore companion serial session is live."""
+        return self._connected
+
     @property
     def is_running(self) -> bool:
         return self._running

tests/test_firmware_flash_routes.py

@@ -149,5 +149,18 @@ def test_erase_flag_omitted_from_cmd_when_false(self):
         self.assertIn("--erase-all", args)
 
 
+class TestMeshcoreSourceConnectedProperty(unittest.TestCase):
+    """Flash stream uses source.connected; SerialSource already exposes it."""
+
+    def test_meshcore_usb_exposes_connected(self):
+        from src.capture.meshcore_usb_source import MeshcoreUsbCaptureSource
+        from src.config import MeshcoreUsbConfig
+
+        source = MeshcoreUsbCaptureSource(MeshcoreUsbConfig())
+        self.assertFalse(source.connected)
+        source._connected = True
+        self.assertTrue(source.connected)
+
+
 if __name__ == "__main__":
     unittest.main()