Master reset T-Mobile myTouch 4G
Re-insert the battery.
Press and hold both the Volume Down key and the Power key. Do not release the volume key,
Release the Volume Down key when the three Android images appear on the
bottom of the screen. The following options dsplay:
Note: If the you are stuck on a screen that says 'HBOOT' and 'FASTBOOT'
without any other options to choose from, it means you have pressed the
Back button. To get to the regular options, press either the Power key
on HBOOT or the Back button.
Press the Volume Down key twice to select FACTORY RESET.
Press the Power key to initiate the master reset.
Wait as the device displays the boot up screen, then shows a picture of
arrows above a device with a progress bar. It then restarts.