Unlock iphone 3gs, unknown ios version or baseband

[iMore Question]

My 3gs was jailbroken and unlocked. Since i wasn't using it anymore, i lent it to a friend who thought it was a good idea to update the phone without asking me. It is stuck on activation screen. I don't know to what version it updated. I have tried using redsn0w but no luck, maybe i'm doing something wrong. Thanks in advance!

 

[Tartarus]

Put your phone in DFU mode, have it restored in iTunes and jailbreak it again.