diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/garmin/GarminCoordinator.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/garmin/GarminCoordinator.java
index f58e9cefd..6b6cc0bc9 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/garmin/GarminCoordinator.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/garmin/GarminCoordinator.java
@@ -2,7 +2,12 @@ package nodomain.freeyourgadget.gadgetbridge.devices.garmin;
 
 import androidx.annotation.NonNull;
 
+import java.util.List;
+
 import nodomain.freeyourgadget.gadgetbridge.GBException;
+import nodomain.freeyourgadget.gadgetbridge.R;
+import nodomain.freeyourgadget.gadgetbridge.activities.devicesettings.DeviceSpecificSettings;
+import nodomain.freeyourgadget.gadgetbridge.activities.devicesettings.DeviceSpecificSettingsScreen;
 import nodomain.freeyourgadget.gadgetbridge.devices.AbstractBLEDeviceCoordinator;
 import nodomain.freeyourgadget.gadgetbridge.entities.DaoSession;
 import nodomain.freeyourgadget.gadgetbridge.entities.Device;
@@ -27,6 +32,16 @@ public abstract class GarminCoordinator extends AbstractBLEDeviceCoordinator {
         return GarminSupport.class;
     }
 
+    @Override
+    public DeviceSpecificSettings getDeviceSpecificSettings(final GBDevice device) {
+        final DeviceSpecificSettings deviceSpecificSettings = new DeviceSpecificSettings();
+
+        final List<Integer> connection = deviceSpecificSettings.addRootScreen(DeviceSpecificSettingsScreen.CONNECTION);
+        connection.add(R.xml.devicesettings_high_mtu);
+
+        return deviceSpecificSettings;
+    }
+
     @Override
     public boolean supportsFindDevice() {
         return true;
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/AbstractDeviceSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/AbstractDeviceSupport.java
index 736366c7e..a37d8bc1c 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/AbstractDeviceSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/AbstractDeviceSupport.java
@@ -745,7 +745,7 @@ public abstract class AbstractDeviceSupport implements DeviceSupport {
         LocalBroadcastManager.getInstance(context).sendBroadcast(messageIntent);
     }
 
-    protected Prefs getDevicePrefs() {
+    public Prefs getDevicePrefs() {
         return new Prefs(GBApplication.getDeviceSpecificSharedPrefs(gbDevice.getAddress()));
     }
 
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/cmfwatchpro/CmfWatchProSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/cmfwatchpro/CmfWatchProSupport.java
index db6152697..36b034280 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/cmfwatchpro/CmfWatchProSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/cmfwatchpro/CmfWatchProSupport.java
@@ -65,7 +65,6 @@ import nodomain.freeyourgadget.gadgetbridge.service.btle.actions.SetDeviceStateA
 import nodomain.freeyourgadget.gadgetbridge.service.serial.GBDeviceProtocol;
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 import nodomain.freeyourgadget.gadgetbridge.util.MediaManager;
-import nodomain.freeyourgadget.gadgetbridge.util.Prefs;
 
 public class CmfWatchProSupport extends AbstractBTLEDeviceSupport implements CmfCharacteristic.Handler {
     private static final Logger LOG = LoggerFactory.getLogger(CmfWatchProSupport.class);
@@ -177,11 +176,6 @@ public class CmfWatchProSupport extends AbstractBTLEDeviceSupport implements Cmf
         mediaManager = new MediaManager(context);
     }
 
-    @Override
-    protected Prefs getDevicePrefs() {
-        return super.getDevicePrefs();
-    }
-
     @Override
     public boolean onCharacteristicChanged(final BluetoothGatt gatt,
                                            final BluetoothGattCharacteristic characteristic) {
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/GarminSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/GarminSupport.java
index 3ded65dbb..e37c02095 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/GarminSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/GarminSupport.java
@@ -1,5 +1,7 @@
 package nodomain.freeyourgadget.gadgetbridge.service.devices.garmin;
 
+import static nodomain.freeyourgadget.gadgetbridge.activities.devicesettings.DeviceSettingsPreferenceConst.PREF_ALLOW_HIGH_MTU;
+
 import android.bluetooth.BluetoothGatt;
 import android.bluetooth.BluetoothGattCharacteristic;
 
@@ -53,7 +55,6 @@ import nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.messages.SetD
 import nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.messages.SupportedFileTypesMessage;
 import nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.messages.SystemEventMessage;
 import nodomain.freeyourgadget.gadgetbridge.util.FileUtils;
-import nodomain.freeyourgadget.gadgetbridge.util.GB;
 import nodomain.freeyourgadget.gadgetbridge.util.StringUtils;
 
 
@@ -120,11 +121,29 @@ public class GarminSupport extends AbstractBTLEDeviceSupport implements ICommuni
             return builder;
         }
 
+        if (getDevicePrefs().getBoolean(PREF_ALLOW_HIGH_MTU, true)) {
+            builder.requestMtu(515);
+        }
+
         communicator.initializeDevice(builder);
 
         return builder;
     }
 
+    @Override
+    public void onMtuChanged(final BluetoothGatt gatt, final int mtu, final int status) {
+        if (mtu < 23) {
+            LOG.warn("Ignoring mtu of {}, too low", mtu);
+            return;
+        }
+        if (!getDevicePrefs().getBoolean(PREF_ALLOW_HIGH_MTU, true)) {
+            LOG.warn("Ignoring mtu change to {} - high mtu is disabled", mtu);
+            return;
+        }
+
+        communicator.onMtuChanged(mtu);
+    }
+
     @Override
     public boolean onCharacteristicChanged(final BluetoothGatt gatt, final BluetoothGattCharacteristic characteristic) {
         final UUID characteristicUUID = characteristic.getUuid();
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/ICommunicator.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/ICommunicator.java
index dd6e5f336..3c483b04b 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/ICommunicator.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/ICommunicator.java
@@ -8,6 +8,8 @@ import nodomain.freeyourgadget.gadgetbridge.service.btle.TransactionBuilder;
 public interface ICommunicator {
     void sendMessage(byte[] message);
 
+    void onMtuChanged(final int mtu);
+
     void initializeDevice(TransactionBuilder builder);
 
     boolean onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic);
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/v1/CommunicatorV1.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/v1/CommunicatorV1.java
index f946de6fd..cfce06ad8 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/v1/CommunicatorV1.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/v1/CommunicatorV1.java
@@ -19,6 +19,11 @@ public class CommunicatorV1 implements ICommunicator {
         this.mSupport = garminSupport;
     }
 
+    @Override
+    public void onMtuChanged(final int mtu) {
+
+    }
+
     @Override
     public void initializeDevice(final TransactionBuilder builder) {
 
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/v2/CommunicatorV2.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/v2/CommunicatorV2.java
index 44a23f086..2c770bcd6 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/v2/CommunicatorV2.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/communicator/v2/CommunicatorV2.java
@@ -23,7 +23,7 @@ public class CommunicatorV2 implements ICommunicator {
     public static final UUID UUID_CHARACTERISTIC_GARMIN_ML_GFDI_SEND = UUID.fromString("6a4e2822-667b-11e3-949a-0800200c9a66"); //VivomoveConstants.UUID_CHARACTERISTIC_GARMIN_ML_GFDI_SEND;
     public static final UUID UUID_CHARACTERISTIC_GARMIN_ML_GFDI_RECEIVE = UUID.fromString("6a4e2812-667b-11e3-949a-0800200c9a66"); //VivomoveConstants.UUID_CHARACTERISTIC_GARMIN_ML_GFDI_RECEIVE;
 
-    public static final int MAX_WRITE_SIZE = 20; //VivomoveConstants.MAX_WRITE_SIZE
+    public int maxWriteSize = 20; //VivomoveConstants.MAX_WRITE_SIZE
     private static final Logger LOG = LoggerFactory.getLogger(CommunicatorV2.class);
     public final CobsCoDec cobsCoDec;
     private final GarminSupport mSupport;
@@ -35,8 +35,14 @@ public class CommunicatorV2 implements ICommunicator {
         this.cobsCoDec = new CobsCoDec();
     }
 
+    @Override
+    public void onMtuChanged(final int mtu) {
+        maxWriteSize = mtu - 3;
+    }
+
     @Override
     public void initializeDevice(final TransactionBuilder builder) {
+
         builder.notify(this.mSupport.getCharacteristic(UUID_CHARACTERISTIC_GARMIN_ML_GFDI_RECEIVE), true);
         builder.write(this.mSupport.getCharacteristic(UUID_CHARACTERISTIC_GARMIN_ML_GFDI_SEND), closeAllServices());
     }
@@ -53,10 +59,10 @@ public class CommunicatorV2 implements ICommunicator {
 //        LOG.debug("SENDING MESSAGE: {} - COBS ENCODED: {}", GB.hexdump(message), GB.hexdump(payload));
         final TransactionBuilder builder = new TransactionBuilder("sendMessage()");
         int remainingBytes = payload.length;
-        if (remainingBytes > MAX_WRITE_SIZE - 1) {
+        if (remainingBytes > maxWriteSize - 1) {
             int position = 0;
             while (remainingBytes > 0) {
-                final byte[] fragment = Arrays.copyOfRange(payload, position, position + Math.min(remainingBytes, MAX_WRITE_SIZE - 1));
+                final byte[] fragment = Arrays.copyOfRange(payload, position, position + Math.min(remainingBytes, maxWriteSize - 1));
                 builder.write(this.mSupport.getCharacteristic(UUID_CHARACTERISTIC_GARMIN_ML_GFDI_SEND), ArrayUtils.addAll(new byte[]{(byte) gfdiHandle}, fragment));
                 position += fragment.length;
                 remainingBytes -= fragment.length;
@@ -168,6 +174,4 @@ public class CommunicatorV2 implements ICommunicator {
             return null;
         }
     }
-
-
 }
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/huami/HuamiSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/huami/HuamiSupport.java
index b33786ab4..e8242eea8 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/huami/HuamiSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/huami/HuamiSupport.java
@@ -4266,10 +4266,6 @@ public abstract class HuamiSupport extends AbstractBTLEDeviceSupport implements
         return (HuamiCoordinator) gbDevice.getDeviceCoordinator();
     }
 
-    protected Prefs getDevicePrefs() {
-        return new Prefs(GBApplication.getDeviceSpecificSharedPrefs(gbDevice.getAddress()));
-    }
-
     @Override
     public void handle2021Payload(short type, byte[] payload) {
         if (type == Huami2021Service.CHUNKED2021_ENDPOINT_COMPAT) {