Apple has pushed iPhone 3.1.2 via iTunes, which weighs in at 241MB and fixes the following issues: a sporadic issue that may cause the iPhone not to wake from sleep, an intermittent issue that may interrupt cellular services until restart and fixes a bug that could cause occasional crashing during video streaming.
The update also includes new carrier settings for AT&T, which is presumed to break tethering functionality as well as any jailbreaks applied to the device. To update, connect the iPhone, open iTunes and click on Check for Updates.
Since I updated my Iphone 3GS with the 3.1.2 update, I am not able to phone any more. A message says that my access to my phone provider is “restricted”.
Was your iPhone unofficially unlocked?
No, I bought it in Switzerland with Swisscom, my carrier, so it is officialy unlocked.