No computer or jailbreak required.
Works with all IOS devices.
Press the plus button right bottom of the screen on your main screen, than free power credits, see offers. After when the offers page appear start to count 13 and than press X on the right top corner and press the power on/off, start to count another 13-14 second and unlock your screen.
The whole method takes 25-27 seconds as you guys can see in the video.