How does one go about unlocking an at&t iphone 4 so it can be used with tmobile?
Contact AT&T, to determine if you qualify for their unlocking procedure.
I am not an at&t customer so they wont unlock it. I want to use my at&t locked phone on tmobile network
If you don't meet their requirements, then you're out of luck. There is no other way to legitimately unlock it. Sell it and buy an unlocked phone or use AT&T.
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