Wow, this acutally did help a lot. Using redsn0w and your hint I was now able to downgrade to 3.0, jailbreak (which flashes the baseband) and then upgrade with pwnd 3.1.2 without a problem. I'm now running jailbroken and unlocked 3.2.1 on my iPhone 2G. Thanks a lot!

Hi folks.
I got an iPhone 2G today. Unfortunately I'm not able to jailbreak it in any way. When I got it it was running iPhone OS 3.1.2 and has never been jailbroken. I tried downgrading it to 3.0 and using redsn0w but this stucks at the "waiting for reboot" message. I tried upgrading with a customized .ipsw to 3.0 or 3.1.2, tried that on a PC and on two MACs, in recovery mode and in DFU mode. The result is always the same: iTunes tries to prepare the iPhone but then ends up with an error (1601). This does not happen using an official .ipsw, but using any custom ipsw built with pwnage tool. What can I try? Thanks for any help!!