How to Unlock iPhone 4 and iPhone 3GS on iOS 6.1
The evasi0n iOS 6.X jailbreak finally offered a jailbreak solution for
iOS 6 devices, including extremely hard-to-jailbreak devices like the
iPhone 5, iPad mini, and iPad 4. The team has also just released a new
application on Cydia that allows you to unlock the iPhone 4 and iPhone
3GS. Read more.