Rewrite USB key reader: raw USB API + retry logic

- Replaced usb-serial-for-android library with raw Android USB API
  (UsbDeviceConnection.bulkTransfer) — the library's testConnection()
  sent a get_status CDC request that the ESP32-S3 USB-JTAG/serial
  controller does not support, causing read failures
- Added CDC control interface setup (line coding + DTR/RTS) to enable
  data flow before sending KEY? command
- Added retry logic: 5 attempts, 1s delay between retries, to handle
  other apps grabbing the USB device first (JTAG/serial debug unit
  triggers multiple system dialogs before our app gets permission)
- Re-lookup ESP device on each retry to handle device path changes
- Removed usb-serial-for-android dependency and JitPack repository

android/app/build.gradle

@@ -34,5 +34,4 @@ android {
 dependencies {
     implementation 'androidx.core:core-ktx:1.12.0'
     implementation 'androidx.appcompat:appcompat:1.6.1'
-    implementation 'com.github.mik3y:usb-serial-for-android:3.7.3'
 }

android/app/src/main/java/com/eddy/atomrelay/UsbKeyReceiver.kt

@@ -4,14 +4,16 @@ import android.app.PendingIntent
 import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
+import android.hardware.usb.UsbConstants
 import android.hardware.usb.UsbDevice
+import android.hardware.usb.UsbDeviceConnection
+import android.hardware.usb.UsbEndpoint
+import android.hardware.usb.UsbInterface
 import android.hardware.usb.UsbManager
 import android.os.Handler
 import android.os.Looper
 import android.util.Log
 import android.widget.Toast
-import com.hoho.android.usbserial.driver.CdcAcmSerialDriver
-import com.hoho.android.usbserial.driver.UsbSerialPort
 import java.nio.charset.StandardCharsets
 
 class UsbKeyReceiver : BroadcastReceiver() {
@@ -20,7 +22,10 @@ class UsbKeyReceiver : BroadcastReceiver() {
         private const val TAG = "UsbKeyReceiver"
         private const val ACTION_USB_PERMISSION = "com.eddy.atomrelay.USB_PERMISSION"
         private const val ESP_VENDOR_ID = 0x303a
-        private const val KEY_TIMEOUT_MS = 3000
+        private const val KEY_TIMEOUT_MS = 5000
+        private const val MAX_RETRIES = 5
+        private const val RETRY_DELAY_MS = 1000L
+        private const val CDC_DATA_INTERFACE_CLASS = 0x0A
     }
 
     override fun onReceive(context: Context, intent: Intent) {
@@ -31,74 +36,154 @@ class UsbKeyReceiver : BroadcastReceiver() {
                 if (device.vendorId != ESP_VENDOR_ID) return
 
                 val usbManager = context.getSystemService(Context.USB_SERVICE) as UsbManager
-                if (usbManager.hasPermission(device)) {
+                val currentDevice = findEspDevice(usbManager) ?: device
-                    Thread { readKey(context, usbManager, device) }.start()
+                if (usbManager.hasPermission(currentDevice)) {
+                    Thread { readKeyRaw(context, usbManager, currentDevice) }.start()
                 } else {
-                    val permIntent = PendingIntent.getBroadcast(
+                    requestPermission(context, usbManager, currentDevice)
-                        context, 0,
-                        Intent(ACTION_USB_PERMISSION)
-                            .setClass(context, UsbKeyReceiver::class.java)
-                            .putExtra(UsbManager.EXTRA_DEVICE, device),
-                        PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
-                    )
-                    usbManager.requestPermission(device, permIntent)
-                    Log.d(TAG, "Requesting USB permission for ${device.deviceName}")
                 }
             }
             ACTION_USB_PERMISSION -> {
-                val device = intent.getParcelableExtra<UsbDevice>(UsbManager.EXTRA_DEVICE) ?: return
+                if (!intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
-                if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
-                    Log.d(TAG, "USB permission granted for ${device.deviceName}")
-                    val usbManager = context.getSystemService(Context.USB_SERVICE) as UsbManager
-                    Thread { readKey(context, usbManager, device) }.start()
-                } else {
                     Log.w(TAG, "USB permission denied")
                     Handler(Looper.getMainLooper()).post {
                         Toast.makeText(context, "USB-toegang geweigerd", Toast.LENGTH_SHORT).show()
                     }
+                    return
+                }
+                Log.d(TAG, "USB permission granted")
+                val usbManager = context.getSystemService(Context.USB_SERVICE) as UsbManager
+                val device = findEspDevice(usbManager)
+                if (device != null) {
+                    Thread { readKeyRaw(context, usbManager, device) }.start()
+                } else {
+                    Log.e(TAG, "ESP device not found after permission grant")
+                    Handler(Looper.getMainLooper()).post {
+                        Toast.makeText(context, "ESP niet (meer) gevonden", Toast.LENGTH_SHORT).show()
+                    }
                 }
             }
         }
     }
 
-    private fun readKey(context: Context, usbManager: UsbManager, device: UsbDevice) {
+    private fun findEspDevice(usbManager: UsbManager): UsbDevice? {
+        return usbManager.deviceList.values.firstOrNull { it.vendorId == ESP_VENDOR_ID }
+    }
+
+    private fun requestPermission(context: Context, usbManager: UsbManager, device: UsbDevice) {
+        val flags = if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.S) {
+            PendingIntent.FLAG_MUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
+        } else {
+            PendingIntent.FLAG_UPDATE_CURRENT
+        }
+        val permIntent = PendingIntent.getBroadcast(
+            context, 0,
+            Intent(context, UsbKeyReceiver::class.java)
+                .setAction(ACTION_USB_PERMISSION),
+            flags
+        )
+        usbManager.requestPermission(device, permIntent)
+        Log.d(TAG, "Requesting USB permission for ${device.deviceName}")
+    }
+
+    private fun readKeyRaw(context: Context, usbManager: UsbManager, device: UsbDevice) {
         val handler = Handler(Looper.getMainLooper())
-        var port: UsbSerialPort? = null
+
+        for (attempt in 1..MAX_RETRIES) {
+            Log.d(TAG, "Read attempt $attempt/$MAX_RETRIES")
+            var connection: UsbDeviceConnection? = null
 
             try {
-            val driver = CdcAcmSerialDriver(device)
+                val currentDevice = findEspDevice(usbManager) ?: device
-            val connection = usbManager.openDevice(device)
+                connection = usbManager.openDevice(currentDevice)
                 if (connection == null) {
-                Log.e(TAG, "Failed to open USB device")
+                    Log.w(TAG, "Attempt $attempt: openDevice returned null")
+                    if (attempt < MAX_RETRIES) {
+                        Thread.sleep(RETRY_DELAY_MS)
+                        continue
+                    }
                     handler.post { Toast.makeText(context, "Kan USB-apparaat niet openen", Toast.LENGTH_SHORT).show() }
                     return
                 }
 
-            val ports = driver.ports
+                val dataInterface = findCdcDataInterface(currentDevice)
-            if (ports.isEmpty()) {
+                if (dataInterface == null) {
-                Log.e(TAG, "No serial ports found")
+                    Log.w(TAG, "Attempt $attempt: no CDC data interface")
-                handler.post { Toast.makeText(context, "Geen serial-poort gevonden", Toast.LENGTH_SHORT).show() }
+                    connection.close()
+                    if (attempt < MAX_RETRIES) {
+                        Thread.sleep(RETRY_DELAY_MS)
+                        continue
+                    }
+                    handler.post { Toast.makeText(context, "Geen CDC interface gevonden op ESP", Toast.LENGTH_SHORT).show() }
                     return
                 }
 
-            port = ports[0]
+                if (!connection.claimInterface(dataInterface, true)) {
-            port.open(connection)
+                    Log.w(TAG, "Attempt $attempt: failed to claim interface")
-            port.setParameters(115200, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE)
+                    connection.close()
-            Log.d(TAG, "Serial port opened, sending KEY?")
+                    if (attempt < MAX_RETRIES) {
+                        Thread.sleep(RETRY_DELAY_MS)
+                        continue
+                    }
+                    handler.post { Toast.makeText(context, "Kan USB interface niet claimen", Toast.LENGTH_SHORT).show() }
+                    return
+                }
 
-            port.purgeHwBuffers(true, true)
+                val epOut = findBulkEndpoint(dataInterface, UsbConstants.USB_DIR_OUT)
+                val epIn = findBulkEndpoint(dataInterface, UsbConstants.USB_DIR_IN)
+                if (epOut == null || epIn == null) {
+                    Log.w(TAG, "Attempt $attempt: missing endpoints")
+                    connection.close()
+                    if (attempt < MAX_RETRIES) {
+                        Thread.sleep(RETRY_DELAY_MS)
+                        continue
+                    }
+                    handler.post { Toast.makeText(context, "USB endpoints niet gevonden", Toast.LENGTH_SHORT).show() }
+                    return
+                }
+
+                Log.d(TAG, "CDC interface claimed, endpoints ready (out max=${epOut.maxPacketSize}, in max=${epIn.maxPacketSize})")
+
+                val controlIntf = findCdcControlInterface(currentDevice)
+                if (controlIntf != null) {
+                    connection.claimInterface(controlIntf, true)
+                    connection.controlTransfer(
+                        UsbConstants.USB_DIR_OUT or UsbConstants.USB_TYPE_CLASS or 0x01,
+                        0x20,
+                        0,
+                        controlIntf.id,
+                        byteArrayOf(0x00, 0xC2.toByte(), 0x01, 0x00, 0x00, 0x00, 0x08),
+                        7,
+                        500
+                    )
+                    connection.controlTransfer(
+                        UsbConstants.USB_DIR_OUT or UsbConstants.USB_TYPE_CLASS or 0x01,
+                        0x22,
+                        3,
+                        controlIntf.id,
+                        null,
+                        0,
+                        500
+                    )
+                    Log.d(TAG, "CDC control interface configured (line coding + DTR/RTS)")
+                } else {
+                    Log.w(TAG, "No CDC control interface found, trying without")
+                }
+
+                Thread.sleep(300)
 
                 val cmd = "KEY?\n".toByteArray(StandardCharsets.US_ASCII)
-            port.write(cmd, 500)
+                val written = connection.bulkTransfer(epOut, cmd, cmd.size, 1000)
+                Log.d(TAG, "Sent KEY? (${written} bytes)")
 
-            Thread.sleep(200)
+                Thread.sleep(300)
 
-            val buf = ByteArray(256)
+                val buf = ByteArray(512)
-            val startTime = System.currentTimeMillis()
                 val sb = StringBuilder()
+                val startTime = System.currentTimeMillis()
 
                 while (System.currentTimeMillis() - startTime < KEY_TIMEOUT_MS) {
-                val len = port.read(buf, 200)
+                    val len = connection.bulkTransfer(epIn, buf, buf.size, 500)
                     if (len > 0) {
                         sb.append(String(buf, 0, len, StandardCharsets.US_ASCII))
                         if (sb.contains("HMAC_KEY:") && sb.contains("\n")) {
@@ -108,7 +193,7 @@ class UsbKeyReceiver : BroadcastReceiver() {
                 }
 
                 val response = sb.toString()
-            Log.d(TAG, "Serial response: $response")
+                Log.d(TAG, "Serial response: ${response.take(200)}")
 
                 val keyLine = response.lines().firstOrNull { it.startsWith("HMAC_KEY:") }
                 if (keyLine != null) {
@@ -121,19 +206,63 @@ class UsbKeyReceiver : BroadcastReceiver() {
                         handler.post {
                             Toast.makeText(context, "HMAC sleutel gelezen van ESP!", Toast.LENGTH_LONG).show()
                         }
+                        return
                     } else {
                         Log.e(TAG, "Invalid key format: length=${hexKey.length}")
-                    handler.post { Toast.makeText(context, "Ongeldig sleutel formaat van ESP", Toast.LENGTH_SHORT).show() }
+                        handler.post { Toast.makeText(context, "Ongeldig sleutel formaat", Toast.LENGTH_SHORT).show() }
+                        return
                     }
                 } else {
-                Log.e(TAG, "No HMAC_KEY line found in response")
+                    Log.w(TAG, "Attempt $attempt: no HMAC_KEY in response, will retry")
-                handler.post { Toast.makeText(context, "Geen sleutel gevonden op de ESP", Toast.LENGTH_SHORT).show() }
+                    connection.close()
+                    connection = null
+                    if (attempt < MAX_RETRIES) {
+                        Thread.sleep(RETRY_DELAY_MS)
+                    }
                 }
             } catch (e: Exception) {
-            Log.e(TAG, "Error reading key: ${e.message}", e)
+                Log.e(TAG, "Attempt $attempt error: ${e.message}", e)
+                if (attempt < MAX_RETRIES) {
+                    Thread.sleep(RETRY_DELAY_MS)
+                } else {
                     handler.post { Toast.makeText(context, "Fout bij uitlezen: ${e.message}", Toast.LENGTH_SHORT).show() }
-        } finally {
-            try { port?.close() } catch (e: Exception) {}
                 }
+            } finally {
+                try { connection?.close() } catch (e: Exception) {}
+            }
+        }
+
+        Log.e(TAG, "All $MAX_RETRIES attempts failed")
+        handler.post { Toast.makeText(context, "Sleutel niet gevonden na $MAX_RETRIES pogingen", Toast.LENGTH_SHORT).show() }
+    }
+
+    private fun findCdcDataInterface(device: UsbDevice): UsbInterface? {
+        for (i in 0 until device.interfaceCount) {
+            val intf = device.getInterface(i)
+            if (intf.interfaceClass == CDC_DATA_INTERFACE_CLASS) {
+                return intf
+            }
+        }
+        return null
+    }
+
+    private fun findCdcControlInterface(device: UsbDevice): UsbInterface? {
+        for (i in 0 until device.interfaceCount) {
+            val intf = device.getInterface(i)
+            if (intf.interfaceClass == 0x02) {
+                return intf
+            }
+        }
+        return null
+    }
+
+    private fun findBulkEndpoint(intf: UsbInterface, direction: Int): UsbEndpoint? {
+        for (i in 0 until intf.endpointCount) {
+            val ep = intf.getEndpoint(i)
+            if (ep.type == UsbConstants.USB_ENDPOINT_XFER_BULK && ep.direction == direction) {
+                return ep
+            }
+        }
+        return null
     }
 }

android/settings.gradle

@@ -10,7 +10,6 @@ dependencyResolutionManagement {
     repositories {
         google()
         mavenCentral()
-        maven { url 'https://jitpack.io' }
     }
 }
 rootProject.name = "AtomRelay"