The iOS 4 was out a few days back and we discussed about it.Unlock iPhone 3GS 4.0 firmware (iOS 4) Now if you have jailbroken your iPhone 3GS with 4.0 firmware, now called the iOS 4, then get ready to unlock it with unltrasn0w 0.92. If you want to unlock iPhone 3GS 4.0 or iOS 4, then here are the steps to do it so that you can use it with any carrier you like.

1. After jailbreaking your iPhone 3GS, open Cydia.

2. Tap on the ” Manage ” option.

3. Now choose the ” Sources ” tab.

4. Tap on the ” Edit ” button.

5. Press ” Add ” to add the source.

6. Now enter ” http://ios4.ultrasn0w.org ” and tap ” Add Source “. Wait till the installation is complete.

7. Now search for ” ultrasn0w 0.92 ” in Cydia.

8. Install the ultrasn0w 0.92 app on your iPhone 3GS.

9. Now just restart your phone and you will be having a completely unlocked iPhone 3GS with iOS 4 in your hand.