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 2f726845b..576c92444 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
@@ -296,7 +296,7 @@ public class CmfWatchProSupport extends AbstractBTLEDeviceSupport implements Cmf
                     LOG.warn("Unexpected serial number payload length: {}, expected {}", payload.length, (payload[0] & 0xff));
                     return;
                 }
-                final String serialNumber = new String(ArrayUtils.subarray(payload, 1, payload.length - 2));
+                final String serialNumber = new String(ArrayUtils.subarray(payload, 1, payload.length));
                 LOG.debug("Got serial number: {}", serialNumber);
                 final GBDeviceEventUpdateDeviceInfo gbDeviceEventUpdateDeviceInfo = new GBDeviceEventUpdateDeviceInfo("SERIAL: ", serialNumber);
                 evaluateGBDeviceEvent(gbDeviceEventUpdateDeviceInfo);