Hello, that is my first time here...... my brothers,gave to me one used iPhone 3gs 5.1.1 (9B206) bb 05.16.05 locked on O2 12.0 I am trying to unlock that but i read about old bootrum and iam not sure if i can or not to do that unlocking because my phone have this Serial Number: QR12781xxxx ! Please help me ! Thanks !