Hey I have an iPhone 3GS and it WAS on 3.1.3 jb. but I tried to install a custom 4.0fw and it wont let me, so now im stuck on restore. I'm not officially using ATT or anything so what do I do? Is there a way to downgrade? I tried all night to get it back to 3.1.2 or 3.1.3 and itunes says im not authorized to use those fw's. then when i try and just go to the custom 4.0 it gives me erros 1600 and 1604. So, IS there ANY way to not have to go to 4.0 official? and if I HAVE to go to 4.0 ofiicial is their a way to jailbreak it on my 3GS or more importantly is there a way to get past the activation insert sim screen?