Samsung GT-i9100 Galaxy S2 hard reset with buttons Galaxy S2 factory reset after rooting
http://imageshack.com/scaled/800x600/30/jrvp.png
PRESS AND HOLD VOLUME UP + Home Button
Keep pressing these 2 buttons + press Power button for 2-3 Seconds
Release only power button, but KEEP pressing Volume up + Home Buttons
With Volume down select wipe data/factory reset (3rd) > Press Power
(VOLUME UP + HOME + POWER buttons)
