Here's the deal. I have a friend's iPhone 5, which she gave me to try to jailbreak. It was formerly on T-mobile (at least that is what she is telling me) and she gave me an active AT&T sim card. Is it possible to jailbreak this phone in it's current state (inactive on any network)? It looks to me as if the phone has been wiped and wants to start from scratch. Upon a certain point, with the new sim card in, it's telling me the sim card is invalid. Any help / guidance sincerely appreciated. Thanks in advance!