- Press & hold down the Volume UP button + Power button
- when the tablet vibrates release the Power button Only
- You have to release the power switch in 3 seconds (no more, no less).
- You have to continue to hold the volume up button after releasing the power button.
- You have to quickly work the screen lock switch as soon as the tablet vibrates as directed in step 5 (still holding the volume button, but not the power button).
- At step 6, when you see the following two messages briefly in the upper left corner of the screen, you have been successful:
Erasing user data...
Erasing cache...
If the tablet shows a recovery error or any other unexpected condition, you may have made some mistake in the procedure. For example, if you hold the power button too long this can cause the device to go into a recovery mode. If you encounter this, don't worry. This is a common and correctable mistake. In such a case, just restart the procedure at Step 1. The procedure can take several practice runs to complete successfully. What follows is the step by step procedure.
source: acertabletforum
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