Earlier iPhone dev team has released the Pwnagetool to jailbreak iPhone 3G/3GS 3.12 firmware. Before proceeding with the iphone 3G/3GS with 3.1.2 firmware ,unlocking process, it needs to be jaibreaked. After you have jailbreaked your iPhone 3G you can use Ultrasn0w tool to unlock it. So here are the steps.
How To Unlock iPhone 3G/3GS 3.12 Firmware with Ultrasn0w
- If you havent jailbreaked your iPhone, Follow this guide on How to Jailbreak iPhone 3G/3GS 3.12 Firmware
- Now go to Cydia and Choose Manage Tab.
- Select Sources, press Edit-Add and add the following address to it.
http://repo666.ultrasn0w.com/ - Now search “ultrasn0w” in Cydia and install Ultrasn0w. After the Ultrasn0w installation of is completed on your iPhone, it will automatically unlock your iPhone 3G/3GS with 3.1.2 Firmware.