Instruction I:


1. Turn on the phone. Unless it is already on, in which case, well, don't turn it off.
2. Now hold down the Volume Down + Power buttons. The phone will soon restart. Done!

Instruction II:


1. First, press & hold the Power button to turn off your device.
2. Now drag the window to the low end of the display.

3. Do nothing for ten seconds and then turn the phone back on. Done.