1. Unplug the power cord and shut the unit off.
2. Press and hold the VOL DOWN and then POWER button at the same time for at least 10-12 seconds until after the start-up screen appears and is joined by some small print at the top of the screen, then let them both go. If the TF booted the way it always does, you have not accomplished the task, try again until you have seen 2 icons (ICS), 4 icons (JB) in the screen.
3. After a few seconds you should see some icons in the middle of the screen – in ICS they are called “Wipe Data” and “Android”. The right “Android” will have a green highlight fading in and out. In JB there are four, the first of which is RCK.
4. Press the VOL DOWN button to select the “Wipe Data” icon then VOL UP to confirm it.