not stuck at reboot screen, but iPhone doesn't reboot so no jailbreak
I successfully restored a previously pwned and unlocked iPhone 2G to version 3.1.3 of the firmware, with an AT&T sim inserted (effectively upgrading the OS from version 3.0.1). However, I'm unable to successfully jailbreak said iPhone. I've tried redsn0w 0.9.2 to no avail:
I left all the options except "already pwned" unchecked (I don't want Cydia). The kernel and ramdisk get uploaded to the iPhone, but the iPhone doesn't actually reboot and is stuck at the black (backlit) screen. Disconnecting and reconnecting the USB cable does nothing. When I forced a reboot by holding down the home and power buttons, I was back to where I started before running redsn0w -- i.e. the "illegal SIM - connect to iTunes". I ran redsn0w again, and the same thing happened! :(
Any ideas as to how to fix this problem??