Before you start, you need to determine the firmware version:
1. Turn on the watch and hold down the SOS button for 3 seconds with the watch untethered
2. In the menu that opens, select Item Test
3. Next, select Version Test and scroll down
4. If you see the green label Spreadtrum SC8541e, you need firmware Version 1
5. If you see the red label Spreadtrum SC8521e, you need firmware Version 2
Version 1 - Link to download the files to update software - Link
Version 1 - Link to download the files to update software - Link