I bought an unlocked, jailbroken iPhone 3gs, and had no problem using T-Mobile with it (4.0.1 firmware). A buddy told me to update to the 4.1, and now I can't do anything with it. Does anyone know how to hack this, or to reset it back to the 4.0.1 firmware? I have no cell phone now, and can't do anything with this phone until I can get some suggestions. Please help!