Instruction I
1. First of all, power up the device.
2. Time to employ some manual dexterity! Press and hold three buttons at the same time - Delete + left Alt+ right Shift. The phone's screen will turn black for a moment.
3. After the screen returns to normal, press and hold Delete + left Alt+ right Shift again. Done.
Instruction II
1. Remove and insert the battery into your phone.
2. Power on the phone.