So my friend has a 3GS, it's running OS 5.1 on baseband 06.15.00, and it's got an old bootrom. Only problem he's not getting any service with his AT&T sim card. I installed ultrasn0w fixer, then ultrasn0w, but that won't work either. I tried using the latest version of redsn0w on his laptop, but when it goes into DFU mode, redsn0w doesn't detect it.
Anyone have any solutions to get this working on?
Thanks in advance