Blacksn0w RC2 for iPhone 3.1.3 on baseband 05.11.07 has been released now and can be downloaded via Cydia.

Blacksn0w RC2 is not an official release by Geohot, but this tool can be easily used to Unlock iPhone 3.1.3 on baseband 05.11.07. Here’s how:

Unlock iPhone 3G/3GS 3.1.3 05.11.07 Baseband

1- Checks your *real* firmware version using your kernel version (this avoids using the reported firmware version which might be “faked”). Only installs if you are really running 3.1.2 or 3.1.3

2- add the source “http://cydia.pushfix.info/” before installation.

3- Checks your baseband version – only installs if 05.11.07

4- Properly backs up and restores your configuration if uninstalled