1. In the first step hold down the Power key for a short while in order to turn off the device.
2. Then press and hold the Volume Down button for about 2-3 seconds.
3. While still holding these keys press the Power key for a short while and release all buttons.
4. Afterwards choose Barcodes by using Volume buttons and to confirm Power key.
5. Well done! You can check here the mose important number defying your device.