Factory reset erase all data from your device's internal storage.
You have a problem with your device or you want to reset your device, you may use factory reset.
PM66, PM70, PM80P
How to Factory Reset PM66, PM70, PM80
If you can turn on the device and use the Settings app,
Navigate to Settings > Backup & reset
Tap Factory data reset
Please be aware that factory reset will erase all data. Tap RESET PHONE to start the factory reset
Tap ERASE EVERYTHING to confirm the factory reset
If you cannot turn on the device,
Press and hold Power + Volume Up + (PM70, PM80P)Home or (PM66)Front Scan buttons simultaneously when turning on the device
After short vibration, release the buttons. Now your device is entered Android Recovery mode
Using Volume(move up&down) and Power(select) buttons, select 'Wipe data/factory reset'
After wiping the data, select 'Reboot system now'