Hello, sorry if this has been addressed but I could not find it.

I have Firmware 03.14.08_G, Version 1.0.2 (1C28), I used iUnlock, and my carrier is T-Mobile.

Is there any easy solution to get this back to an out of the box state so I can cancel my T-mo account and start up with At&t? I believe when I used iUnlock (before that i tried anysim) I had my att sim in the phone for most of the process, will i need to get a new sim?

Thanks for any help!