For all the eager upgraders out there who have pulled the trigger on the recently released iOS 4.0, the iPhone Dev Team have released the first Unlock tool for the 05.13.04 baseband. The ultrasn0w 0.93 unlock tool also unlocks older basebands uptill 04.26.08.

Ultrasn0w Unlock iOS 4

Although the official jailbreak tool hasn’t been announced yet by the iPhone Dev Team, the iOS 4.0 leaked builds were successfully jailbroken using the redsn0w 0.9.5 beta 5. You can try that jailbreak here.

Note: Disabling of 3G is recommended while unlocking.

How to Unlock iOS 4.0 Baseband 05.13.04/ 04.26.08 on iPhone 3G/3GS

• Jailbreak iOS 4.0 using Redsn0w (0.9.5beta 5 here, the full release is about to release soon)
• Now start Cydia and go to Manage>sources>edit section
• Add Rep0666.ultrasn0w.com as source
• Now search for Ultrasn0w 0.93 and click on install
• Let Ultrasn0w 0.93 complete the installation.
• Once you reboot your iPhone after installation (restart may take upto 90 seconds for iPhone to find unlocked carrier) you can enjoy your unlocked iPhone 3G/3GS on iOS4.0 with your unlocked carrier.

[via blogsdna]