diff --git a/packages/quick_blue/android/src/main/AndroidManifest.xml b/packages/quick_blue/android/src/main/AndroidManifest.xml
index 919bc9c..6dbadaa 100644
--- a/packages/quick_blue/android/src/main/AndroidManifest.xml
+++ b/packages/quick_blue/android/src/main/AndroidManifest.xml
@@ -5,10 +5,8 @@
     <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
 
     <!-- legacy for Android 11 or lower -->
-    <uses-permission android:name="android.permission.BLUETOOTH"
-        android:maxSdkVersion="30" />
-    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"
-        android:maxSdkVersion="30" />
+    <uses-permission android:name="android.permission.BLUETOOTH" />
+    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
     <!-- legacy for Android 9 or lower -->
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
diff --git a/packages/quick_blue/android/src/main/kotlin/com/example/quick_blue/QuickBluePlugin.kt b/packages/quick_blue/android/src/main/kotlin/com/example/quick_blue/QuickBluePlugin.kt
index 7193b9b..b0a1761 100644
--- a/packages/quick_blue/android/src/main/kotlin/com/example/quick_blue/QuickBluePlugin.kt
+++ b/packages/quick_blue/android/src/main/kotlin/com/example/quick_blue/QuickBluePlugin.kt
@@ -80,120 +80,128 @@ class QuickBluePlugin: FlutterPlugin, MethodCallHandler, EventChannel.StreamHand
   fun trace() = Arrays.toString(Throwable().stackTrace)
 
   override fun onMethodCall(@NonNull call: MethodCall, @NonNull result: Result) {
-    when (call.method) {
-      "isBluetoothAvailable" -> {
-        result.success(bluetoothManager.adapter.isEnabled)
-      }
-      "startScan" -> {
-        val serviceUUIDs = call.argument<ArrayList<String>>("serviceUUIDs")!!
-        if (serviceUUIDs != null && serviceUUIDs.size > 0) {
-          val filters: ArrayList<ScanFilter> = ArrayList()
-          for (serviceUUID in serviceUUIDs) {
-            val filter = ScanFilter.Builder()
-                    .setServiceUuid(parseToParcelUuid(serviceUUID))
+    try {
+      when (call.method) {
+        "isBluetoothAvailable" -> {
+          result.success(bluetoothManager.adapter.isEnabled)
+        }
+        "startScan" -> {
+          val serviceUUIDs = call.argument<ArrayList<String>>("serviceUUIDs")
+          if (serviceUUIDs != null && serviceUUIDs.size > 0) {
+            val filters: ArrayList<ScanFilter> = ArrayList()
+            for (serviceUUID in serviceUUIDs) {
+              val filter = ScanFilter.Builder()
+                      .setServiceUuid(parseToParcelUuid(serviceUUID))
+                      .build()
+              filters.add(filter)
+            }
+
+            val settings = ScanSettings.Builder()
+                    .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
                     .build()
-            filters.add(filter)
-          }
-
-          val settings = ScanSettings.Builder()
-                  .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
-                  .build()
 
-          bluetoothManager.adapter.bluetoothLeScanner?.startScan(filters, settings, scanCallback)
-        } else {
-          bluetoothManager.adapter.bluetoothLeScanner?.startScan(scanCallback)
+            bluetoothManager.adapter.bluetoothLeScanner?.startScan(filters, settings, scanCallback)
+          } else {
+            bluetoothManager.adapter.bluetoothLeScanner?.startScan(scanCallback)
+          }
+          result.success(null)
         }
-        result.success(null)
-      }
-      "stopScan" -> {
-        bluetoothManager.adapter.bluetoothLeScanner?.stopScan(scanCallback)
-        result.success(null)
-      }
-      "connect" -> {
-        val deviceId = call.argument<String>("deviceId")!!
-        if (knownGatts.find { it.device.address == deviceId } != null) {
-          return result.success(null)
+        "stopScan" -> {
+          bluetoothManager.adapter.bluetoothLeScanner?.stopScan(scanCallback)
+          result.success(null)
         }
-        val remoteDevice = bluetoothManager.adapter.getRemoteDevice(deviceId)
-        val gatt = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-          remoteDevice.connectGatt(context, false, gattCallback, BluetoothDevice.TRANSPORT_LE)
-        } else {
-          remoteDevice.connectGatt(context, false, gattCallback)
+        "connect" -> {
+          val deviceId = call.argument<String>("deviceId")!!
+          if (knownGatts.find { it.device.address == deviceId } != null) {
+            return result.success(null)
+          }
+          val remoteDevice = bluetoothManager.adapter.getRemoteDevice(deviceId)
+          val gatt = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+            remoteDevice.connectGatt(context, false, gattCallback, BluetoothDevice.TRANSPORT_LE)
+          } else {
+            remoteDevice.connectGatt(context, false, gattCallback)
+          }
+          knownGatts.add(gatt)
+          result.success(null)
+          // TODO connecting
         }
-        knownGatts.add(gatt)
-        result.success(null)
-        // TODO connecting
-      }
-      "disconnect" -> {
-        val deviceId = call.argument<String>("deviceId")!!
-        val gatt = knownGatts.find { it.device.address == deviceId }
-                ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
-        cleanConnection(gatt)
-        result.success(null)
-        //FIXME If `disconnect` is called before BluetoothGatt.STATE_CONNECTED
-        // there will be no `disconnected` message any more
-      }
-      "discoverServices" -> {
-        val deviceId = call.argument<String>("deviceId")!!
-        val gatt = knownGatts.find { it.device.address == deviceId }
-                ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
-        gatt.discoverServices()
-        result.success(null)
-      }
-      "setNotifiable" -> {
-        val deviceId = call.argument<String>("deviceId")!!
-        val service = call.argument<String>("service")!!
-        val characteristic = call.argument<String>("characteristic")!!
-        val bleInputProperty = call.argument<String>("bleInputProperty")!!
-        val gatt = knownGatts.find { it.device.address == deviceId }
-                ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
-        val c = gatt.getCharacteristic(service, characteristic)
-                ?: return result.error("IllegalArgument", "Unknown characteristic: $characteristic", trace())
-        gatt.setNotifiable(c, bleInputProperty)
-        result.success(null)
-      }
-      "readValue" -> {
-        val deviceId = call.argument<String>("deviceId")!!
-        val service = call.argument<String>("service")!!
-        val characteristic = call.argument<String>("characteristic")!!
-        val gatt = knownGatts.find { it.device.address == deviceId }
-                ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
-        val c = gatt.getCharacteristic(service, characteristic)
-                ?: return result.error("IllegalArgument", "Unknown characteristic: $characteristic", trace())
-        if (gatt.readCharacteristic(c))
+        "disconnect" -> {
+          val deviceId = call.argument<String>("deviceId")!!
+          val gatt = knownGatts.find { it.device.address == deviceId }
+                  ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
+          cleanConnection(gatt)
           result.success(null)
-        else
-          result.error("Characteristic unavailable", null, trace())
-      }
-      "writeValue" -> {
-        val deviceId = call.argument<String>("deviceId")!!
-        val service = call.argument<String>("service")!!
-        val characteristic = call.argument<String>("characteristic")!!
-        val value = call.argument<ByteArray>("value")!!
-        val gatt = knownGatts.find { it.device.address == deviceId }
-                ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
-        val c = gatt.getCharacteristic(service, characteristic)
-                ?: return result.error("IllegalArgument", "Unknown characteristic: $characteristic", trace())
-        c.value = value
-        if (gatt.writeCharacteristic(c))
+          //FIXME If `disconnect` is called before BluetoothGatt.STATE_CONNECTED
+          // there will be no `disconnected` message any more
+        }
+        "discoverServices" -> {
+          val deviceId = call.argument<String>("deviceId")!!
+          val gatt = knownGatts.find { it.device.address == deviceId }
+                  ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
+          gatt.discoverServices()
           result.success(null)
-        else
-          result.error("Characteristic unavailable", null, trace())
-      }
-      "requestMtu" -> {
-        val deviceId = call.argument<String>("deviceId")!!
-        val expectedMtu = call.argument<Int>("expectedMtu")!!
-        val gatt = knownGatts.find { it.device.address == deviceId }
-                ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
-        val success = gatt.requestMtu(expectedMtu)
-        if (success)
+        }
+        "setNotifiable" -> {
+          val deviceId = call.argument<String>("deviceId")!!
+          val service = call.argument<String>("service")!!
+          val characteristic = call.argument<String>("characteristic")!!
+          val bleInputProperty = call.argument<String>("bleInputProperty")!!
+          val gatt = knownGatts.find { it.device.address == deviceId }
+                  ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
+          val s = gatt.getService(UUID.fromString(service))
+                  ?: return result.error("IllegalArgument", "Unknown service: $service", trace())
+          val c = s.getCharacteristic(UUID.fromString(characteristic))
+                  ?: return result.error("IllegalArgument", "Unknown characteristic: $characteristic", trace())
+          gatt.setNotifiable(c, bleInputProperty)
           result.success(null)
-        else
-          result.error("Unable to set MTU", null, trace())
-      }
-      else -> {
-        result.notImplemented()
+        }
+        "readValue" -> {
+          val deviceId = call.argument<String>("deviceId")!!
+          val service = call.argument<String>("service")!!
+          val characteristic = call.argument<String>("characteristic")!!
+          val gatt = knownGatts.find { it.device.address == deviceId }
+                  ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
+          val c = gatt.getCharacteristic(service, characteristic)
+                  ?: return result.error("IllegalArgument", "Unknown characteristic: $characteristic", trace())
+          if (gatt.readCharacteristic(c))
+            result.success(null)
+          else
+            result.error("Characteristic unavailable", null, trace())
+        }
+        "writeValue" -> {
+          val deviceId = call.argument<String>("deviceId")!!
+          val service = call.argument<String>("service")!!
+          val characteristic = call.argument<String>("characteristic")!!
+          val value = call.argument<ByteArray>("value")!!
+          val gatt = knownGatts.find { it.device.address == deviceId }
+                  ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
+          val c = gatt.getCharacteristic(service, characteristic)
+                  ?: return result.error("IllegalArgument", "Unknown characteristic: $characteristic", trace())
+          c.value = value
+          if (gatt.writeCharacteristic(c)) {
+            result.success(null)
+          } else {
+            result.error("Characteristic unavailable", null, trace())
+          }
+        }
+        "requestMtu" -> {
+          val deviceId = call.argument<String>("deviceId")!!
+          val expectedMtu = call.argument<Int>("expectedMtu")!!
+          val gatt = knownGatts.find { it.device.address == deviceId }
+                  ?: return result.error("IllegalArgument", "Unknown deviceId: $deviceId", trace())
+          val success = gatt.requestMtu(expectedMtu)
+          if (success)
+            result.success(null)
+          else
+            result.error("Unable to set MTU", null, trace())
+        }
+        else -> {
+          result.notImplemented()
+        }
       }
+    } catch (e: Throwable) {
+      e.printStackTrace()
+      result.error("Error", "Error", trace())
     }
   }
 
@@ -363,7 +371,7 @@ fun Short.toByteArray(byteOrder: ByteOrder = ByteOrder.LITTLE_ENDIAN): ByteArray
         ByteBuffer.allocate(2 /*Short.SIZE_BYTES*/).order(byteOrder).putShort(this).array()
 
 fun BluetoothGatt.getCharacteristic(service: String, characteristic: String): BluetoothGattCharacteristic? =
-        getService(UUID.fromString(service)).getCharacteristic(UUID.fromString(characteristic))
+        getService(UUID.fromString(service))?.getCharacteristic(UUID.fromString(characteristic))
 
 private val DESC__CLIENT_CHAR_CONFIGURATION = UUID.fromString("00002902-0000-1000-8000-00805f9b34fb")
 
@@ -374,8 +382,10 @@ fun BluetoothGatt.setNotifiable(gattCharacteristic: BluetoothGattCharacteristic,
     "indication" -> BluetoothGattDescriptor.ENABLE_INDICATION_VALUE to true
     else -> BluetoothGattDescriptor.DISABLE_NOTIFICATION_VALUE to false
   }
-  descriptor.value = value
-  setCharacteristicNotification(descriptor.characteristic, enable) && writeDescriptor(descriptor)
+  if (setCharacteristicNotification(gattCharacteristic, enable) && descriptor != null) {
+    descriptor.value = value
+    writeDescriptor(descriptor)
+  }
 }
 const val baseBluetoothUuidPostfix = "0000-1000-8000-00805F9B34FB"
 
diff --git a/packages/quick_blue/lib/src/method_channel_quick_blue.dart b/packages/quick_blue/lib/src/method_channel_quick_blue.dart
index ab5d886..8c57a77 100644
--- a/packages/quick_blue/lib/src/method_channel_quick_blue.dart
+++ b/packages/quick_blue/lib/src/method_channel_quick_blue.dart
@@ -92,8 +92,7 @@ class MethodChannelQuickBlue extends QuickBluePlatform {
       if (message['ServiceState'] == 'discovered') {
         String deviceId = message['deviceId'];
         String service = message['service'];
-        List<String> characteristics =
-            (message['characteristics'] as List).cast();
+        List<String> characteristics = ((message['characteristics'] ?? []) as List).cast();
         onServiceDiscovered?.call(deviceId, service, characteristics);
       }
     } else if (message['characteristicValue'] != null) {
diff --git a/packages/quick_blue/windows/quick_blue_plugin.cpp b/packages/quick_blue/windows/quick_blue_plugin.cpp
index 31d184d..e4331bd 100644
--- a/packages/quick_blue/windows/quick_blue_plugin.cpp
+++ b/packages/quick_blue/windows/quick_blue_plugin.cpp
@@ -24,6 +24,10 @@
 #include <algorithm>
 #include <iomanip>
 
+#include <codecvt>
+#include <locale>
+#include <iostream>
+
 #define GUID_FORMAT "%08x-%04hx-%04hx-%02hhx%02hhx-%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
 #define GUID_ARG(guid) guid.Data1, guid.Data2, guid.Data3, guid.Data4[0], guid.Data4[1], guid.Data4[2], guid.Data4[3], guid.Data4[4], guid.Data4[5], guid.Data4[6], guid.Data4[7]
 
@@ -620,6 +624,10 @@ namespace
   winrt::fire_and_forget QuickBluePlugin::ConnectAsync(uint64_t bluetoothAddress)
   {
     auto device = co_await BluetoothLEDevice::FromBluetoothAddressAsync(bluetoothAddress);
+    if (!device) {
+        OutputDebugString((L"ConnectAsync null device! "+ std::to_wstring(bluetoothAddress) +L"\n").c_str());
+        co_return;
+    }
     auto servicesResult = co_await device.GetGattServicesAsync();
     if (servicesResult.Status() != GattCommunicationStatus::Success)
     {