diff --git a/android/app/build.gradle b/android/app/build.gradle
index b091c04..71f9cf9 100644
--- a/android/app/build.gradle
+++ b/android/app/build.gradle
@@ -4,14 +4,14 @@ plugins {
 }
 
 android {
-    namespace 'com.eddy.atomrelay'
+    namespace 'nl.eddydevink.sylda'
     // compileSdk/targetSdk stays on 34 (Android 14) by deliberate choice. The target audience
     // consists of physically disabled users who are very reluctant to update their phones. Staying
     // on API 34 maximises device compatibility. Re-evaluate when the user base has migrated.
     compileSdk 34
 
     defaultConfig {
-        applicationId "com.eddy.atomrelay"
+        applicationId "nl.eddydevink.sylda"
         minSdk 26
         targetSdk 34
         versionCode 1
diff --git a/android/app/src/main/AndroidManifest.xml b/android/app/src/main/AndroidManifest.xml
index 5059ef3..44d9552 100644
--- a/android/app/src/main/AndroidManifest.xml
+++ b/android/app/src/main/AndroidManifest.xml
@@ -13,7 +13,7 @@
 
     <application
         android:allowBackup="false"
-        android:label="Atom Relay"
+        android:label="@string/app_name"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
 
@@ -30,6 +30,15 @@
         <activity
             android:name=".SettingsActivity"
             android:label="Instellingen"
-            android:parentActivityName=".MainActivity"/>
+            android:parentActivityName=".MainActivity"
+            android:launchMode="singleTop"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
+            </intent-filter>
+            <meta-data
+                android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
+                android:resource="@xml/device_filter" />
+        </activity>
     </application>
 </manifest>
\ No newline at end of file
diff --git a/android/app/src/main/assets/firmware/firmware.bin b/android/app/src/main/assets/firmware/firmware.bin
index e5bf28e..4f086b7 100644
Binary files a/android/app/src/main/assets/firmware/firmware.bin and b/android/app/src/main/assets/firmware/firmware.bin differ
diff --git a/android/app/src/main/java/com/eddy/atomrelay/BleRelayManager.kt b/android/app/src/main/java/nl/eddydevink/sylda/BleRelayManager.kt
similarity index 99%
rename from android/app/src/main/java/com/eddy/atomrelay/BleRelayManager.kt
rename to android/app/src/main/java/nl/eddydevink/sylda/BleRelayManager.kt
index 713c683..0f137f9 100644
--- a/android/app/src/main/java/com/eddy/atomrelay/BleRelayManager.kt
+++ b/android/app/src/main/java/nl/eddydevink/sylda/BleRelayManager.kt
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-package com.eddy.atomrelay
+package nl.eddydevink.sylda
 
 import android.Manifest
 import android.annotation.SuppressLint
diff --git a/android/app/src/main/java/com/eddy/atomrelay/BleStatus.kt b/android/app/src/main/java/nl/eddydevink/sylda/BleStatus.kt
similarity index 92%
rename from android/app/src/main/java/com/eddy/atomrelay/BleStatus.kt
rename to android/app/src/main/java/nl/eddydevink/sylda/BleStatus.kt
index 19a0046..110aac8 100644
--- a/android/app/src/main/java/com/eddy/atomrelay/BleStatus.kt
+++ b/android/app/src/main/java/nl/eddydevink/sylda/BleStatus.kt
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-package com.eddy.atomrelay
+package nl.eddydevink.sylda
 
 enum class BleStatus {
     Scanning,
diff --git a/android/app/src/main/java/com/eddy/atomrelay/EspFlasher.kt b/android/app/src/main/java/nl/eddydevink/sylda/EspFlasher.kt
similarity index 99%
rename from android/app/src/main/java/com/eddy/atomrelay/EspFlasher.kt
rename to android/app/src/main/java/nl/eddydevink/sylda/EspFlasher.kt
index ba3377b..7a1b75d 100644
--- a/android/app/src/main/java/com/eddy/atomrelay/EspFlasher.kt
+++ b/android/app/src/main/java/nl/eddydevink/sylda/EspFlasher.kt
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-package com.eddy.atomrelay
+package nl.eddydevink.sylda
 
 import android.content.Context
 import android.hardware.usb.UsbConstants
diff --git a/android/app/src/main/java/com/eddy/atomrelay/MainActivity.kt b/android/app/src/main/java/nl/eddydevink/sylda/MainActivity.kt
similarity index 99%
rename from android/app/src/main/java/com/eddy/atomrelay/MainActivity.kt
rename to android/app/src/main/java/nl/eddydevink/sylda/MainActivity.kt
index e67457e..81adfec 100644
--- a/android/app/src/main/java/com/eddy/atomrelay/MainActivity.kt
+++ b/android/app/src/main/java/nl/eddydevink/sylda/MainActivity.kt
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-package com.eddy.atomrelay
+package nl.eddydevink.sylda
 
 import android.content.Intent
 import android.content.pm.PackageManager
diff --git a/android/app/src/main/java/com/eddy/atomrelay/PrefsHelper.kt b/android/app/src/main/java/nl/eddydevink/sylda/PrefsHelper.kt
similarity index 97%
rename from android/app/src/main/java/com/eddy/atomrelay/PrefsHelper.kt
rename to android/app/src/main/java/nl/eddydevink/sylda/PrefsHelper.kt
index 31147f9..5b123ac 100644
--- a/android/app/src/main/java/com/eddy/atomrelay/PrefsHelper.kt
+++ b/android/app/src/main/java/nl/eddydevink/sylda/PrefsHelper.kt
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-package com.eddy.atomrelay
+package nl.eddydevink.sylda
 
 import android.content.Context
 import android.content.SharedPreferences
diff --git a/android/app/src/main/java/com/eddy/atomrelay/SettingsActivity.kt b/android/app/src/main/java/nl/eddydevink/sylda/SettingsActivity.kt
similarity index 91%
rename from android/app/src/main/java/com/eddy/atomrelay/SettingsActivity.kt
rename to android/app/src/main/java/nl/eddydevink/sylda/SettingsActivity.kt
index e1946e1..a860c32 100644
--- a/android/app/src/main/java/com/eddy/atomrelay/SettingsActivity.kt
+++ b/android/app/src/main/java/nl/eddydevink/sylda/SettingsActivity.kt
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-package com.eddy.atomrelay
+package nl.eddydevink.sylda
 
 import android.app.AlertDialog
 import android.app.PendingIntent
@@ -52,7 +52,7 @@ class SettingsActivity : AppCompatActivity() {
         private const val FLUSH_TIMEOUT_MS = 100
         private const val READ_CHUNK_TIMEOUT_MS = 500
         private const val CDC_CONTROL_TIMEOUT_MS = 500
-        private const val ACTION_USB_PERMISSION = "com.eddy.atomrelay.USB_PERMISSION"
+        private const val ACTION_USB_PERMISSION = "nl.eddydevink.sylda.USB_PERMISSION"
         private const val STYLE_SPINNER = 0
         private const val STYLE_HORIZONTAL = 1
         private const val USB_READ_BUF_SIZE = 512
@@ -60,11 +60,17 @@ class SettingsActivity : AppCompatActivity() {
         private const val UUID_HEX_LEN = 32
         private const val UUID_BYTE_COUNT = 16
         private const val HMAC_BYTE_COUNT = 32
+        private const val VERSION_TIMEOUT_MS = 3000L
+        private const val REBOOT_WAIT_MS = 5000L
+        private const val REBOOT_POLL_MS = 500L
+        private const val REBOOT_MAX_WAIT_MS = 15000L
+        private const val EXPECTED_FIRMWARE_VERSION = "1"
     }
 
     private enum class UsbAction { NONE, EXCHANGE_KEY, FLASH }
 
     private var currentAction = UsbAction.NONE
+    private var expectingReboot = false
     private var progressDialog: AlertDialog? = null
     private var dialog: AlertDialog? = null
     private var flasherJob: Job? = null
@@ -109,6 +115,7 @@ class SettingsActivity : AppCompatActivity() {
             if (intent.action == UsbManager.ACTION_USB_DEVICE_DETACHED) {
                 val device = intent.getParcelableExtra<UsbDevice>(UsbManager.EXTRA_DEVICE)
                 if (device?.vendorId == ESP_VENDOR_ID) {
+                    if (expectingReboot) return
                     if (dialog != null && currentAction == UsbAction.NONE) {
                         dialog?.dismiss()
                         dialog = null
@@ -129,16 +136,10 @@ class SettingsActivity : AppCompatActivity() {
         supportActionBar?.setDisplayHomeAsUpEnabled(true)
         supportActionBar?.title = getString(R.string.title_settings)
 
-        findViewById<Button>(R.id.exchangeKeyButton).setOnClickListener {
-            startKeyExchange()
-        }
-
         findViewById<Button>(R.id.flashFirmwareButton).setOnClickListener {
             startFlashing()
         }
 
-        findViewById<TextView>(R.id.buildNumber).text = getString(R.string.build_number, BuildConfig.BUILD_NUMBER)
-
         registerReceiver(usbAttachedReceiver, IntentFilter(UsbManager.ACTION_USB_DEVICE_ATTACHED), Context.RECEIVER_EXPORTED)
         registerReceiver(usbPermissionReceiver, IntentFilter(ACTION_USB_PERMISSION), Context.RECEIVER_NOT_EXPORTED)
         registerReceiver(usbDetachedReceiver, IntentFilter(UsbManager.ACTION_USB_DEVICE_DETACHED), Context.RECEIVER_EXPORTED)
@@ -147,6 +148,13 @@ class SettingsActivity : AppCompatActivity() {
         setupLabelEditTexts()
     }
 
+    override fun onNewIntent(intent: Intent) {
+        super.onNewIntent(intent)
+        if (intent.action == UsbManager.ACTION_USB_DEVICE_ATTACHED && currentAction == UsbAction.NONE) {
+            finish()
+        }
+    }
+
     override fun onResume() {
         super.onResume()
         val current = PrefsHelper.getPrefs(this).getString(PrefsHelper.PREF_THEME, "system") ?: "system"
@@ -274,7 +282,6 @@ class SettingsActivity : AppCompatActivity() {
                             .putString(PrefsHelper.PREF_UUID, result.deviceUuid)
                             .putString(PrefsHelper.PREF_KEY, result.hexKey)
                             .apply()
-                        Toast.makeText(this@SettingsActivity, getString(R.string.key_read_success), Toast.LENGTH_LONG).show()
                         cleanupAction()
                         setResult(RESULT_SCAN)
                         finish()
@@ -319,6 +326,26 @@ class SettingsActivity : AppCompatActivity() {
     }
 
     private fun doFlashing(usbManager: UsbManager, device: UsbDevice) {
+        showProgressDialog(getString(R.string.title_firmware_flash), getString(R.string.msg_checking_version), STYLE_SPINNER)
+
+        lifecycleScope.launch {
+            val version = readEspVersion(usbManager, device)
+            if (version == EXPECTED_FIRMWARE_VERSION && !expectingReboot) {
+                Log.d(TAG, "Firmware version $version matches, skipping flash")
+                progressDialog?.dismiss()
+                progressDialog = null
+                currentAction = UsbAction.EXCHANGE_KEY
+                doKeyExchange(usbManager, device)
+                return@launch
+            }
+            Log.d(TAG, "Firmware version ${version ?: "none"}, flashing")
+            progressDialog?.dismiss()
+            progressDialog = null
+            doFlashInner(usbManager, device)
+        }
+    }
+
+    private fun doFlashInner(usbManager: UsbManager, device: UsbDevice) {
         dialog?.dismiss()
         dialog = null
         showProgressDialog(getString(R.string.title_firmware_flash), getString(R.string.msg_initializing), STYLE_HORIZONTAL)
@@ -337,19 +364,14 @@ class SettingsActivity : AppCompatActivity() {
             try {
                 flasher.flashDevice(usbManager, device, progressCallback)
                 if (isFinishing || isDestroyed) return@launch
-                currentAction = UsbAction.NONE
+                expectingReboot = true
+                currentAction = UsbAction.EXCHANGE_KEY
                 progressDialog?.dismiss()
                 progressDialog = null
-                dialog = AlertDialog.Builder(this@SettingsActivity)
-                    .setTitle(getString(R.string.title_firmware_flash))
-                    .setMessage(getString(R.string.msg_flash_complete))
-                    .setPositiveButton(getString(R.string.button_close)) { d, _ ->
-                        d.dismiss()
-                        dialog = null
-                    }
-                    .setCancelable(true)
-                    .setOnCancelListener { dialog = null }
-                    .show()
+                showWaitingDialog(
+                    getString(R.string.title_firmware_flash),
+                    getString(R.string.msg_env_waiting_reboot)
+                )
             } catch (e: kotlinx.coroutines.CancellationException) {
                 cleanupAction()
                 throw e
@@ -412,6 +434,7 @@ class SettingsActivity : AppCompatActivity() {
 
     private fun cleanupAction() {
         currentAction = UsbAction.NONE
+        expectingReboot = false
         dialog?.dismiss()
         dialog = null
         progressDialog?.dismiss()
@@ -440,6 +463,30 @@ class SettingsActivity : AppCompatActivity() {
         data class Error(val resId: Int, val arg: String? = null) : KeyResult()
     }
 
+    private fun readEspVersion(usbManager: UsbManager, device: UsbDevice): String? {
+        val intf = UsbUtils.findCdcDataInterface(device) ?: return null
+        val connection = usbManager.openDevice(device) ?: return null
+        if (!connection.claimInterface(intf, true)) { connection.close(); return null }
+
+        val epOut = UsbUtils.findBulkEndpoint(intf, UsbConstants.USB_DIR_OUT)
+            ?: run { connection.close(); return null }
+        val epIn = UsbUtils.findBulkEndpoint(intf, UsbConstants.USB_DIR_IN)
+            ?: run { connection.close(); return null }
+
+        return try {
+            setupCdcControl(connection, device)
+            Thread.sleep(KEY_SETTLE_MS)
+            val cmd = "VERSION?\n".toByteArray(StandardCharsets.US_ASCII)
+            connection.bulkTransfer(epOut, cmd, cmd.size, USB_BULK_TIMEOUT_MS)
+            Thread.sleep(RESPONSE_WAIT_MS)
+            val response = readResponse(connection, epIn, VERSION_TIMEOUT_MS)
+            val versionLine = response.lines().firstOrNull { it.startsWith("BUILD_NR:") }
+            versionLine?.removePrefix("BUILD_NR:")?.trim()
+        } finally {
+            connection.close()
+        }
+    }
+
     private fun readKeyFromEsp(usbManager: UsbManager, device: UsbDevice, appUuid: String?, appKey: String?): KeyResult? {
         val intf = UsbUtils.findCdcDataInterface(device)
             ?: return KeyResult.Error(R.string.err_no_cdc)
@@ -643,7 +690,6 @@ class SettingsActivity : AppCompatActivity() {
                     .putString(PrefsHelper.PREF_UUID, espUuid)
                     .putString(PrefsHelper.PREF_KEY, espKey)
                     .apply()
-                Toast.makeText(this, getString(R.string.key_read_success), Toast.LENGTH_LONG).show()
                 cleanupAction()
                 setResult(RESULT_SCAN)
                 finish()
@@ -692,7 +738,6 @@ class SettingsActivity : AppCompatActivity() {
                 progressDialog = null
                 when (result) {
                     is KeyResult.Success -> {
-                        Toast.makeText(this@SettingsActivity, getString(R.string.key_read_success), Toast.LENGTH_LONG).show()
                         cleanupAction()
                         setResult(RESULT_SCAN)
                         finish()
diff --git a/android/app/src/main/java/com/eddy/atomrelay/UsbSerialTransport.kt b/android/app/src/main/java/nl/eddydevink/sylda/UsbSerialTransport.kt
similarity index 98%
rename from android/app/src/main/java/com/eddy/atomrelay/UsbSerialTransport.kt
rename to android/app/src/main/java/nl/eddydevink/sylda/UsbSerialTransport.kt
index 28e86e3..5f4f0e1 100644
--- a/android/app/src/main/java/com/eddy/atomrelay/UsbSerialTransport.kt
+++ b/android/app/src/main/java/nl/eddydevink/sylda/UsbSerialTransport.kt
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-package com.eddy.atomrelay
+package nl.eddydevink.sylda
 
 import android.hardware.usb.UsbConstants
 import android.hardware.usb.UsbDeviceConnection
diff --git a/android/app/src/main/java/com/eddy/atomrelay/UsbUtils.kt b/android/app/src/main/java/nl/eddydevink/sylda/UsbUtils.kt
similarity index 97%
rename from android/app/src/main/java/com/eddy/atomrelay/UsbUtils.kt
rename to android/app/src/main/java/nl/eddydevink/sylda/UsbUtils.kt
index 56e5836..085c28f 100644
--- a/android/app/src/main/java/com/eddy/atomrelay/UsbUtils.kt
+++ b/android/app/src/main/java/nl/eddydevink/sylda/UsbUtils.kt
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-package com.eddy.atomrelay
+package nl.eddydevink.sylda
 
 import android.hardware.usb.UsbConstants
 import android.hardware.usb.UsbDevice
diff --git a/android/app/src/main/res/layout/activity_main.xml b/android/app/src/main/res/layout/activity_main.xml
index b8b0040..1849496 100644
--- a/android/app/src/main/res/layout/activity_main.xml
+++ b/android/app/src/main/res/layout/activity_main.xml
@@ -4,14 +4,28 @@
     android:layout_height="match_parent"
     android:padding="16dp">
 
-    <ImageButton
-        android:id="@+id/settingsButton"
-        android:layout_width="48dp"
-        android:layout_height="48dp"
+    <LinearLayout
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
         android:layout_gravity="end|top"
-        android:src="@drawable/ic_settings"
-        android:background="?android:attr/selectableItemBackgroundBorderless"
-        android:contentDescription="@string/cd_settings" />
+        android:orientation="horizontal"
+        android:gravity="center_vertical">
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/settings_label"
+            android:textSize="14sp"
+            android:layout_marginEnd="4dp" />
+
+        <ImageButton
+            android:id="@+id/settingsButton"
+            android:layout_width="40dp"
+            android:layout_height="40dp"
+            android:src="@drawable/ic_settings"
+            android:background="?android:attr/selectableItemBackgroundBorderless"
+            android:contentDescription="@string/cd_settings" />
+    </LinearLayout>
 
     <LinearLayout
         android:layout_width="wrap_content"
diff --git a/android/app/src/main/res/layout/activity_settings.xml b/android/app/src/main/res/layout/activity_settings.xml
index 8837376..b05419f 100644
--- a/android/app/src/main/res/layout/activity_settings.xml
+++ b/android/app/src/main/res/layout/activity_settings.xml
@@ -12,19 +12,6 @@
         android:textSize="16sp"
         android:layout_marginBottom="24dp" />
 
-    <Button
-        android:id="@+id/exchangeKeyButton"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:text="@string/button_key_exchange" />
-
-    <View
-        android:layout_width="match_parent"
-        android:layout_height="1dp"
-        android:background="?android:attr/listDivider"
-        android:layout_marginTop="24dp"
-        android:layout_marginBottom="24dp" />
-
     <TextView
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
@@ -139,12 +126,4 @@
         android:layout_height="0dp"
         android:layout_weight="1" />
 
-    <TextView
-        android:id="@+id/buildNumber"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:textSize="12sp"
-        android:textColor="?android:attr/textColorSecondary"
-        android:gravity="center" />
-
 </LinearLayout>
diff --git a/android/app/src/main/res/values/strings.xml b/android/app/src/main/res/values/strings.xml
index 734035f..71a570d 100644
--- a/android/app/src/main/res/values/strings.xml
+++ b/android/app/src/main/res/values/strings.xml
@@ -1,36 +1,35 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <string name="app_name">Atom Relay</string>
+    <string name="app_name">Sylda</string>
     <string name="settings">Instellingen</string>
 
     <!-- MainActivity status -->
-    <string name="status_default">Disconnected</string>
+    <string name="status_default">Niet verbonden</string>
     <string name="status_discovering_services">Verbonden, services zoeken…</string>
     <string name="status_connecting">Verbinden…</string>
-    <string name="status_connected">Connected</string>
+    <string name="status_connected">Verbonden</string>
     <string name="status_service_error">Servicefout</string>
-    <string name="status_service_not_found">Service not found</string>
+    <string name="status_service_not_found">Service niet gevonden</string>
     <string name="status_comm_error">Communicatiefout</string>
-    <string name="status_no_key">Geen HMAC sleutel - open Instellingen</string>
+    <string name="status_no_key">Geen sleutel — open Instellingen</string>
     <string name="status_permissions_denied">Tik hier om Bluetooth-toegang in te stellen</string>
-    <string name="status_bluetooth_disabled">Bluetooth not enabled</string>
-    <string name="status_scanning">Scanning…</string>
-    <string name="status_device_not_found">Device not found</string>
-    <string name="status_wrong_device">Verkeerd apparaat — opnieuw scannen…</string>
-    <string name="button_retry_scan">Opnieuw scannen</string>
+    <string name="status_bluetooth_disabled">Bluetooth uitgeschakeld</string>
+    <string name="status_wrong_device">Verkeerd apparaat — opnieuw zoeken…</string>
+    <string name="status_scanning">Zoeken…</string>
+    <string name="status_device_not_found">Apparaat niet gevonden</string>
+    <string name="button_retry_scan">Opnieuw zoeken</string>
 
     <!-- MainActivity UI -->
     <string name="cd_settings">Instellingen</string>
-    <string name="button_on">ON</string>
-    <string name="button_hold">HOLD</string>
+    <string name="settings_label">instellingen</string>
+    <string name="button_on">AAN</string>
+    <string name="button_hold">VAST</string>
 
     <!-- SettingsActivity -->
     <string name="title_settings">Instellingen</string>
     <string name="msg_settings_intro">Sluit de ESP aan op USB en kies een actie.</string>
-    <string name="button_key_exchange">Sleutel Uitwisselen</string>
-    <string name="msg_flash_mode_help">Sluit de ESP aan via USB. De app reset de ESP automatisch naar download-modus.</string>
-    <string name="button_firmware_flash">Firmware Flashen</string>
-    <string name="build_number">Buildnummer: %s</string>
+    <string name="msg_flash_mode_help">Sluit de module aan op de USB-poort.</string>
+    <string name="button_firmware_flash">Firmware bijwerken</string>
     <string name="usb_access_denied">USB-toegang geweigerd</string>
     <string name="key_read_success">Beveiligingssleutel gelezen</string>
     <string name="key_exchange_failed">Sleutel uitwisselen mislukt - probeer opnieuw</string>
@@ -57,7 +56,9 @@
     <string name="msg_reading_key">Sleutel uitlezen…</string>
     <string name="msg_flash_download_mode">Sluit de ESP aan via USB om te flashen.</string>
     <string name="msg_initializing">Initialiseren…</string>
-    <string name="msg_flash_complete">Firmware geflashed!\n\nDe ESP herstart automatisch. Sleutels blijven behouden in NVS.</string>
+    <string name="msg_checking_version">Firmware versie controleren…</string>
+    <string name="msg_env_waiting_reboot">Wachten op ESP herstart…</string>
+    <string name="msg_flash_complete">Firmware geflashed!\n\nSleutels worden nu uitgelezen…</string>
     <string name="button_close">Sluiten</string>
     <string name="button_cancel">Annuleren</string>
 
diff --git a/android/app/src/main/res/xml/device_filter.xml b/android/app/src/main/res/xml/device_filter.xml
new file mode 100644
index 0000000..092927f
--- /dev/null
+++ b/android/app/src/main/res/xml/device_filter.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <usb-device vendor-id="12346" product-id="4097" />
+</resources>
diff --git a/platformio.ini b/platformio.ini
index f9a9638..4f488bb 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -13,5 +13,5 @@ build_flags =
     -DCONFIG_BT_NIMBLE_ENABLED
 lib_deps =
     h2zero/NimBLE-Arduino@^2
-upload_port = /dev/ttyACM0
+upload_port = /dev/ttyACM1
 upload_speed = 115200
\ No newline at end of file
diff --git a/src/main.cpp b/src/main.cpp
index ffb428c..e674ecb 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -22,6 +22,7 @@
 #define NVS_NAMESPACE "hmac"
 #define NVS_KEY_NAME  "key"
 #define NVS_UUID_NAME "uuid"
+#define FIRMWARE_VERSION "1"
 
 NimBLECharacteristic *pCharacteristic;
 bool deviceConnected = false;
@@ -250,6 +251,9 @@ void loop() {
                 } else {
                     Serial.println("NO_KEY");
                 }
+            } else if (serialBuf == "VERSION?") {
+                Serial.print("BUILD_NR:");
+                Serial.println(FIRMWARE_VERSION);
             } else if (serialBuf.startsWith("SET_KEY:")) {
                 String hex = serialBuf.substring(8);
                 hex.toUpperCase();