ATT unlocked my iPhone 3GS (iOS 6). I am able to get voice fromStraight Talk but I can't get data. I don't have the Settings -> Network menu option so I can not enter the MMS information. Do I have any options?
The carrier restrictions are still applied that are not allowing you to change APN settings. With the Straight Talk SIM installed, you should be able to see them, but it sounds as if the AT&T carrier file is still blocking the access to the APN area.
How much does AT&T pay Apple to ignore this? I bought a $600 unlocked phone that had nothing to do with AT&T. If I want to use a AT&T MVNO and set the APN to not use AT&T servers that should be allowed.