1. At first remove the back cover and the battery for a couple of seconds.
2. Then put the battery and the cover back in.
3. Finally, power on the phone by holding the Power button.
1. If the display is off, press the Power to turn it back on.
2. Afterwards press and hold the Volume Down + Power button at the same time for a short while.
3. Well done! The device should vibrate and reboot.