How to hard reset a Samsung Galaxy GT-i5800? My Samsung Galaxy GT-i5800 has had the wrong pass entered too many times, and now it's not opening up. So how do I do a factory reset on it, since all the workarounds I've tried (phoning it, mashing keys, putting 'null' as the password') haven't worked?
Reboot into recovery, where you can select the option to factory reset (scroll up/down with the volume keys, use power to select).

Two ways to get into recovery:


Install the Android SDK on your computer and run adb reboot recovery
Power off the phone, hold down both volume buttons and (while holding) click the power button.  Release the volume buttons when recovery appears.