If your T-Mobile G1 Google smartphone is not responding or is frozen, you may have to opt for a hard reset. Here’s how:
1. Turn the G1 off. If it’s frozen on, take the battery out and put it back in the unit.
2. Hold the Home and Power keys down at same time for about 25 seconds. You will see a yellow triangle screen with exclamation point in the middle.
Now to wipe the device clean:
3. Press Alt+L.
4. Press Alt+W for a factory reset.
5. Press the Home and Back keys again for about 25 seconds.
The device should then reset again and the hard reset is complete.