Hello, I'm having a problem with my 3gs. It is a locked phone. It was running 4.3.5 and was working fine. Now after upgrading it to 5.0.1 it doesn't seem to detect the sim card and thus it is impossible to activate it. Its baseband has been upgraded to 06.15.00 (it was on 05.15.04) I tried downgrading it to both 4.3.5 and 4.2.1 nothing changes. It doesn't detect the sim card. Is there a solution ? Thanks !