Though Apple have released a new update to the iPhone firmware that is iOS 4.0.2, its baseband have not been updated along with it.Unlock iOS 4.0.2 with Ultrasn0w So you could still unlock the 05.13.04 baseband on iOS 4.0.2 using Ultrasn0w 1.1-1 version. Here are the instructions to unlock iOS 4.0.2 with Ultrasn0w 1.1-1.

NOTE : There is no jailbreak tool at the moment for jailbreaking the iPhone 3GS and 4 on iOS 4.0.2. Only the iPhone 3G could be jailbroken using Redsn0w. The guide to do that is posted here. So after a jailbreak method for the iPhone 3GS and 4 on iOS 4.0.2 is released, you could jailbreak it using this method.

1. Jailbreak your device.

2. Open Cydia.

3. Choose the ” Manage ” tab at the bottom of the screen.

4. Select ” Sources “.

5. Tap on ” Edit ” and then on ” Add “.

Unlock iOS 4.0.2 with Ultrasn0w

6. Type in ” ” and tap on ” Add Source “.

7. Once the process completes, search for ” Ultrasn0w 1.1-1 ” in Cydia and install this application to unlock iOS 4.0.2.

Unlock iOS 4.0.2 with Ultrasn0w

8. Reboot your iPhone and it will be unlocked on iOS 4.0.2.

That’s all! You have successfully unlocked iOS 4.0.2 on your iPhone using Ultrasn0w 1.1-1.