Ultrasn0w 0.93 has just been released that can unlock iOS4 on baseband 04.26.08, 05.11.07, 05.12.01 and 05.13.04. It has not been tested with iPhone 4 as yet but considering that it adds support for 05.13.04 unlock, it can possibly unlock iPhone 4 too, nothing final on that though. It will work like charm to unlock iPhone 3GS & iPhone 3G on iOS4. Here are step by step instructions:
Before you Begin: Don’t forget to disable 3G, if you’re using T-Mobile USA.
How to Unlock iOS4
Step 1: Jailbreak iOS 4 with redsn0w 0.9.5 (iPhone 3G only, for now).
Step 2: Run Cydia from SpringBoard.
Step 3: Tap on “Edit”, then hit “Add”, a prompt should appear asking “Enter Cydia/APT URL”.
Step 4: Enter http://repo666.ultrasn0w.com/ and hit “Add Source”, then tap on “Return to Cydia”.
Step 5: Once the process completes, search for ultrasn0w 0.93 in Cydia and install it.
Step 6: After installation, reboot your iPhone.
That’s it. Your iPhone should be unlocked now. Enjoy!
If you are iPhone 3GS user, wait for release of sn0wbreeze 1.6 that is expected to jailbreak iPhone 3GS on iOS4.