The recently released iPhone 3.1.2 update also includes a carrier update for AT&T iPhone 3G and iPhone 3GS users. The carrier is updated to AT&T 5.6. The baseband/modem firmware for the iPhone 3.1.2 update still remains at 05.11.07 (which currenty cannot be unlocked). How to update iPhone 3.1.2 carrier settings 1. Download and install the [...]