This guide and tutorial will show you how to unlock iPhone 3.1.3 usingUltraSn0w or BlackSn0w, depending on your iPhone baseband.
The first step is to jailbreak your iPhone 3.1.3, either with RedSn0w or with PwnageTool. Note that PwnageTool is the preferred method as it helps preserve the baseband.
You can use UltraSn0w to unlock these basebands:
- 04.26.08
- 05.11.07
- 05.12.01
- 05.13.04
To find out what your baseband is, go to Settings > General > About > Modem Firmware.