diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/EventHandler.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/EventHandler.java
index d4f44101f..602ca5c85 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/EventHandler.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/EventHandler.java
@@ -55,5 +55,5 @@ public interface EventHandler {
 
     void onAddCalendarEvent(CalendarEventSpec calendarEventSpec);
 
-    void onDeleteCalendarEvent(int type, long id);
+    void onDeleteCalendarEvent(byte type, long id);
 }
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/impl/GBDeviceService.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/impl/GBDeviceService.java
index 6c51e6b29..2e598eacf 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/impl/GBDeviceService.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/impl/GBDeviceService.java
@@ -238,7 +238,7 @@ public class GBDeviceService implements DeviceService {
     }
 
     @Override
-    public void onDeleteCalendarEvent(int type, long id) {
+    public void onDeleteCalendarEvent(byte type, long id) {
         Intent intent = createIntent().setAction(ACTION_DELETE_CALENDAREVENT)
                 .putExtra(EXTRA_CALENDAREVENT_TYPE, type)
                 .putExtra(EXTRA_CALENDAREVENT_ID, id);
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/model/CalendarEventSpec.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/model/CalendarEventSpec.java
index 7f52b2a2d..438123e49 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/model/CalendarEventSpec.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/model/CalendarEventSpec.java
@@ -1,11 +1,11 @@
 package nodomain.freeyourgadget.gadgetbridge.model;
 
 public class CalendarEventSpec {
-    public static final int TYPE_UNKNOWN = 0;
-    public static final int TYPE_SUNRISE = 1;
-    public static final int TYPE_SUNSET = 2;
+    public static final byte TYPE_UNKNOWN = 0;
+    public static final byte TYPE_SUNRISE = 1;
+    public static final byte TYPE_SUNSET = 2;
 
-    public int type;
+    public byte type;
     public long id;
     public int timestamp;
     public int durationInSeconds;
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/DeviceCommunicationService.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/DeviceCommunicationService.java
index ed7edc018..fdafa5265 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/DeviceCommunicationService.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/DeviceCommunicationService.java
@@ -282,7 +282,7 @@ public class DeviceCommunicationService extends Service implements SharedPrefere
             case ACTION_ADD_CALENDAREVENT: {
                 CalendarEventSpec calendarEventSpec = new CalendarEventSpec();
                 calendarEventSpec.id = intent.getLongExtra(EXTRA_CALENDAREVENT_ID, -1);
-                calendarEventSpec.type = intent.getIntExtra(EXTRA_CALENDAREVENT_TYPE, -1);
+                calendarEventSpec.type = intent.getByteExtra(EXTRA_CALENDAREVENT_TYPE, (byte) -1);
                 calendarEventSpec.timestamp = intent.getIntExtra(EXTRA_CALENDAREVENT_TIMESTAMP, -1);
                 calendarEventSpec.durationInSeconds = intent.getIntExtra(EXTRA_CALENDAREVENT_DURATION, -1);
                 calendarEventSpec.title = intent.getStringExtra(EXTRA_CALENDAREVENT_TITLE);
@@ -292,7 +292,7 @@ public class DeviceCommunicationService extends Service implements SharedPrefere
             }
             case ACTION_DELETE_CALENDAREVENT: {
                 long id = intent.getLongExtra(EXTRA_CALENDAREVENT_ID, -1);
-                int type = intent.getIntExtra(EXTRA_CALENDAREVENT_TYPE, -1);
+                byte type = intent.getByteExtra(EXTRA_CALENDAREVENT_TYPE, (byte) -1);
                 mDeviceSupport.onDeleteCalendarEvent(type, id);
                 break;
             }
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/ServiceDeviceSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/ServiceDeviceSupport.java
index 6753f27e1..019722b54 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/ServiceDeviceSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/ServiceDeviceSupport.java
@@ -279,7 +279,7 @@ public class ServiceDeviceSupport implements DeviceSupport {
     }
 
     @Override
-    public void onDeleteCalendarEvent(int type, long id) {
+    public void onDeleteCalendarEvent(byte type, long id) {
         if (checkBusy("delete calendar event")) {
             return;
         }
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/MiBandSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/MiBandSupport.java
index ea2d4d7cf..444e59ee9 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/MiBandSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/MiBandSupport.java
@@ -389,7 +389,7 @@ public class MiBandSupport extends AbstractBTLEDeviceSupport {
     }
 
     @Override
-    public void onDeleteCalendarEvent(int type, long id) {
+    public void onDeleteCalendarEvent(byte type, long id) {
         // not supported
     }
 
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/pebble/PebbleProtocol.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/pebble/PebbleProtocol.java
index a3e4b02cd..9901f85ec 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/pebble/PebbleProtocol.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/pebble/PebbleProtocol.java
@@ -241,6 +241,8 @@ public class PebbleProtocol extends GBDeviceProtocol {
 
     static final byte LENGTH_UUID = 16;
 
+    static final long GB_UUID_MASK = 0x4742474200L;
+
     // base is -5
     private static final String[] hwRevisions = {
             // Emulator
@@ -479,12 +481,12 @@ public class PebbleProtocol extends GBDeviceProtocol {
                 iconId = PebbleIconID.TIMELINE_CALENDAR;
         }
 
-        return encodeTimelinePin(new UUID(calendarEventSpec.type, id), calendarEventSpec.timestamp, (short) calendarEventSpec.durationInSeconds, iconId, calendarEventSpec.title, calendarEventSpec.description);
+        return encodeTimelinePin(new UUID(GB_UUID_MASK | calendarEventSpec.type, id), calendarEventSpec.timestamp, (short) calendarEventSpec.durationInSeconds, iconId, calendarEventSpec.title, calendarEventSpec.description);
     }
 
     @Override
-    public byte[] encodeDeleteCalendarEvent(int type, long id) {
-        return encodeBlobdb(new UUID(type, id), BLOBDB_DELETE, BLOBDB_PIN, null);
+    public byte[] encodeDeleteCalendarEvent(byte type, long id) {
+        return encodeBlobdb(new UUID(GB_UUID_MASK | type, id), BLOBDB_DELETE, BLOBDB_PIN, null);
     }
 
     @Override
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/pebble/PebbleSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/pebble/PebbleSupport.java
index 9414f0653..b0bc3b47d 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/pebble/PebbleSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/pebble/PebbleSupport.java
@@ -129,7 +129,7 @@ public class PebbleSupport extends AbstractSerialDeviceSupport {
     }
 
     @Override
-    public void onDeleteCalendarEvent(int type, long id) {
+    public void onDeleteCalendarEvent(byte type, long id) {
         if (reconnect()) {
             super.onDeleteCalendarEvent(type, id);
         }
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/serial/AbstractSerialDeviceSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/serial/AbstractSerialDeviceSupport.java
index 18be585d9..78e15667d 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/serial/AbstractSerialDeviceSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/serial/AbstractSerialDeviceSupport.java
@@ -196,7 +196,7 @@ public abstract class AbstractSerialDeviceSupport extends AbstractDeviceSupport
     }
 
     @Override
-    public void onDeleteCalendarEvent(int type, long id) {
+    public void onDeleteCalendarEvent(byte type, long id) {
         byte[] bytes = gbDeviceProtocol.encodeDeleteCalendarEvent(type, id);
         sendToDevice(bytes);
     }
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/serial/GBDeviceProtocol.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/serial/GBDeviceProtocol.java
index 79337b5d2..a226c0947 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/serial/GBDeviceProtocol.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/serial/GBDeviceProtocol.java
@@ -70,7 +70,7 @@ public abstract class GBDeviceProtocol {
         return null;
     }
 
-    public byte[] encodeDeleteCalendarEvent(int type, long id) {
+    public byte[] encodeDeleteCalendarEvent(byte type, long id) {
         return null;
     }
 
diff --git a/app/src/test/java/nodomain/freeyourgadget/gadgetbridge/service/TestDeviceSupport.java b/app/src/test/java/nodomain/freeyourgadget/gadgetbridge/service/TestDeviceSupport.java
index 45eea6ebf..8070cb1eb 100644
--- a/app/src/test/java/nodomain/freeyourgadget/gadgetbridge/service/TestDeviceSupport.java
+++ b/app/src/test/java/nodomain/freeyourgadget/gadgetbridge/service/TestDeviceSupport.java
@@ -137,7 +137,7 @@ public class TestDeviceSupport extends AbstractDeviceSupport {
     }
 
     @Override
-    public void onDeleteCalendarEvent(int type, long id) {
+    public void onDeleteCalendarEvent(byte type, long id) {
 
     }