I got an unlock G1 phone and is using it on my AT&T sim card. However, I found my G1 screen sometimes goes back unpredictably, looks like screen timeout, but faster than the timeout value I set (1 min). What's bad, I cannot get it back from this black screen, whatever key I press. Usually you can revive it by pressing red button and "Menu", then draw your unlock pattern, but my phone just don't have any response to the buttons. What's strange, it's not stuck, the OS is obviously running, if you remember the button sequence and your pattern, you can still operate it blindly. I even succeeded in dailing a number without seeing a thing on screen. This abnormal black screen will last a few minutes and repair itself. It looks like screen's problem, but it didn't happen all the time, about just once a day or so. but when it's black, the phone is just not USABLE AT ALL. Even there is an incoming call, it won't showing anything but just keep ringing. (yes, you can pick up and answer the call). Has anyone seen similar problem?