Hi, accidentally upgraded to the latest version of iOS (4.2.1, I think, this is as of yesterday (12/18/2010)), and then realized I had screwed the phone over in terms of using it on Tmobile. Finally i used redsnow to unlock it, everything works just there is no service. Tried removing the sim card and doing airplane mode re-inserting sim card, did not work. Any advice what to do? The modem or baseband version is 05.15.04, and the firmware is 4.2.1 (8C148).

Any advice is appreciated!