Fix(firmware): Disable serial/USB updates for ESP32 devices (#4283)

Author: jamesarich

feature/firmware/src/main/kotlin/org/meshtastic/feature/firmware/FirmwareUpdateManager.kt

@@ -63,7 +63,12 @@ constructor(
     fun dfuProgressFlow(): Flow<DfuInternalState> = nordicDfuHandler.progressFlow()
 
     private fun getHandler(hardware: DeviceHardware): FirmwareUpdateHandler = when {
-        radioPrefs.isSerial() -> usbUpdateHandler
+        radioPrefs.isSerial() -> {
+            if (isEsp32Architecture(hardware.architecture)) {
+                error("Serial/USB firmware update not supported for ESP32 devices from the app")
+            }
+            usbUpdateHandler
+        }
         radioPrefs.isBle() -> {
             if (isEsp32Architecture(hardware.architecture)) {
                 esp32OtaUpdateHandler

feature/firmware/src/main/kotlin/org/meshtastic/feature/firmware/FirmwareUpdateViewModel.kt

@@ -147,6 +147,7 @@ constructor(
         checkForUpdates()
     }
 
+    @Suppress("LongMethod")
     fun checkForUpdates() {
         updateJob?.cancel()
         updateJob =
@@ -174,14 +175,18 @@ constructor(
                             _selectedRelease.value = release
                             val dismissed = bootloaderWarningDataSource.isDismissed(address)
                             val firmwareUpdateMethod =
-                                if (radioPrefs.isSerial()) {
-                                    FirmwareUpdateMethod.Usb
-                                } else if (radioPrefs.isBle()) {
-                                    FirmwareUpdateMethod.Ble
-                                } else if (radioPrefs.isTcp()) {
-                                    FirmwareUpdateMethod.Wifi
-                                } else {
-                                    FirmwareUpdateMethod.Unknown
+                                when {
+                                    radioPrefs.isSerial() -> {
+                                        // ESP32 Serial updates are not supported from the app yet.
+                                        if (deviceHardware.isEsp32Arc) {
+                                            FirmwareUpdateMethod.Unknown
+                                        } else {
+                                            FirmwareUpdateMethod.Usb
+                                        }
+                                    }
+                                    radioPrefs.isBle() -> FirmwareUpdateMethod.Ble
+                                    radioPrefs.isTcp() -> FirmwareUpdateMethod.Wifi
+                                    else -> FirmwareUpdateMethod.Unknown
                                 }
                             _state.value =
                                 FirmwareUpdateState.Ready(

feature/settings/src/main/kotlin/org/meshtastic/feature/settings/SettingsViewModel.kt

@@ -128,14 +128,18 @@ constructor(
                 } else if (radioPrefs.isBle() || radioPrefs.isSerial() || radioPrefs.isTcp()) {
                     val hwModel = node.user.hwModel.number
                     val hw = deviceHardwareRepository.getDeviceHardwareByModel(hwModel).getOrNull()
-                    // Support both Nordic DFU (requiresDfu) and ESP32 Unified OTA (supportsUnifiedOta)
                     val capabilities = Capabilities(node.metadata?.firmwareVersion)
+                    val isSerial = radioPrefs.isSerial()
 
                     // ESP32 Unified OTA is only supported via BLE or WiFi (TCP), not USB Serial.
-                    val isEsp32OtaSupported =
-                        hw?.isEsp32Arc == true && capabilities.supportsEsp32Ota && !radioPrefs.isSerial()
+                    val isEsp32OtaSupported = hw?.isEsp32Arc == true && capabilities.supportsEsp32Ota && !isSerial
 
-                    flow { emit(hw?.requiresDfu == true || isEsp32OtaSupported) }
+                    // Nordic DFU/USB update is supported for NRF52/RP2040.
+                    // For ESP32, we do NOT support Serial updates from the app yet, even if requiresDfu is true
+                    // (which might be set for S3 native USB, but is currently unused by our handlers).
+                    val isDfuSupported = hw?.requiresDfu == true && hw.isEsp32Arc != true
+
+                    flow { emit(isDfuSupported || isEsp32OtaSupported) }
                 } else {
                     flowOf(false)
                 }