I bought a used iPhone 3g unlocked/jailbroken running 4.0.2 After realising how much lag there is on iphone 3g i decided to downgrade to 3.1.3. I have downgraded, now I am stuck at the iPhone activation screen. My final goal is to go from iphone activation screen to having this unit unlocked so I can use it with tmobile. What is the best route to take in order to accomplish this. Please be as specific as possible, I'm a noob. Thank You.