I know you can’t load in custom carrier under 3.1.2 but I assume if its jailbroken you can edit the files on the iPhone. Is it possible to tether Jailbroken iPhone 3.1.2 by editing carrier files? Can you tether on 3.1.2 by editing the carrier files? If yes, then how to go about it? I would really appreciate if someone can assist me regarding this. I hope to hear at the earliest from you guys out there.