I got the 3gs, nice iphone :)
But my friend has a 2g, he has deleted everything. Now it does not boot. I've got it in DFU mode and made an ipsw file. First 3.1.3, now 3.1.2. It says in both versions there is no sim card installed.
What am I doing wrong, I've used PwnageTool 3.1.5 :fail
iClarified - iPhone - How to Unlock/Jailbreak Your iPhone 2G on OS 3.1.3 Using PwnageTool (Mac)

