I upgraded my jailbroken iPhone 3G on OS 3.1.3 to iOS4. I tried jailbreaking with RedSnow and later Pwnage but both seem to leave my 3G un-jailbroken. No big deal - I could live with an un-jailbroken 3G. However, what I could not live with was a very slow 3G iPhone and most importantly, an un-usable 3G. Outside of any wifi access, my iPhone could not get any data connection. So I really want to revert back to OS 3.1.3. Is this possible? If yes, how can I do so? Many thanks.