Huawei Mate 8 hard reset using buttons
1. Turn off your Android Huawei Mate 8 phone.
2. Press and hold both Volume UP + POWER buttons for about 10sec. until HUAWEI logo shows up and EMUI recovery menu displayed.
3. Select Wipe data/Factory reset. (VOL down or up to move)
4. Confirm with power.
5. Confirm wipe off all user data? Press power to confirm again.
Factory reset process will be finished when 100% done under EMUI logo.
After all is done press power to reboot system now.
After data wipe has completed you are done. resetting Huawei Mate 8 done.
Or if your phone is responding to screen input, then open Settings from the Applications menu. Tap Backup & reset > Factory data reset; click Reset phone and then Erase everything to format your phone.
Firmware upgrade on Huawei Mate 8
Power off your phone. Copy the dload/update.app in the root directory of the microSD card. Insert it. Press the VOLUME UP and VOLUME DOWN key, and then press the POWER key to power on the phone and enter the Software Upgrade Mode. After the progress bar stop, the phone will restart.