I updated my G1 Dev Phone with one of the HTC Hero roms floating around and it had stock T-Mobile firmware on it apparently (I see the T-Mobile boot screen for example). Problem? I cannot seem to restore the image back to the developer version. I have downloaded it from HTC, and placed it on a SD card as update.zip (and yes I verified its not named update.zip.zip) and it just gives me the "No valid signature" error and refuses to update. Crap. I have re-downloaded it multiple times and all of that stuff, but it fails every time with the no valid signature error. I cannot activate the phone to get to the desktop either as I am not a T-Mobile customer (AT&T). Am I screwed?