here is how you factory data reset your phone:
- Power off the G1
- Hold Home Key + End key for 20 seconds or until you see a "triangle with an exclamation point and a picture of the G1"
- Open the QWERTY keyboard and hit Alt+W
If you just need temp access and you can log into the google account associated with phone. Then you can: (With phone on) go to play.google.com from a pc. log in. and search for lock screen bypass. select your device and choose install. give it a few minutes to complete. reboot phone and wait for a bit and you will see the screen lock bypass app show up. click add admin account. sometimes it will throw you back to lock. just reboot and do it again. once you are at screen lock bypass app after adding admin account press BACK (pressing home will usually result in lock screen). And when you first boot phone its good to wait at least 2 - 3 minutes before pressing back to home screen. (I see better result and less lockscreen hiccups.) once you are finished you can reboot phone again and when bypass pops up you can uninstall from there. While in backup your data
and do a factory data reset afterwords to get back into your phone properly. Good Luck