some fixes again

python_app/hardware_full/librevna_driver/transport/usb.py

@@ -173,12 +173,21 @@ class USBTransport:
         self._rx_thread = None
 
         if self._handle is not None:
-            self._handle.releaseInterface(self.INTERFACE)
-            self._handle.close()
+            # Always release AND close the handle, even if releaseInterface raises on
+            # a vanished/changed device. Otherwise the handle leaks with the interface
+            # still claimed, and every subsequent connect() fails forever with
+            # "Failed to claim USB interface" (LIBUSB_ERROR_BUSY) — the device never
+            # recovers after a hot-unplug/replug. close() releases the claim at the OS
+            # level regardless, so reconnect can claim it again.
+            with suppress(usb1.USBError):
+                self._handle.releaseInterface(self.INTERFACE)
+            with suppress(usb1.USBError):
+                self._handle.close()
             self._handle = None
 
         if self._ctx is not None:
-            self._ctx.close()
+            with suppress(usb1.USBError):
+                self._ctx.close()
             self._ctx = None
 
         logger.info("USB disconnected (serial=%s)", self.connected_serial)