How to unlock carrier locked iPhone 3GS
I just found an old 3GS (A1303) in my drawer my brother gave me ages ago. I forgot the pin so had to factory reset it. During reactivation, it says the SIM card is not supported by the carrier according to the activation server so it must have been a carrier locked phone. My brother cannot remember which carrier it used and we don't live in the US anymore. Because the phone is still in the pre-activation stage, I cannot find out the IMEI.
Can I ask if there is anyway to reactivate it please? I don't need to use the phone function but it would be fun to play around with iOS 6 again...
Much appreciated.
iPhone 3G S