Those having iPhone 3G may already know that the support for their device is already removed on iOS 4.3 firmware and onwards . Firmware iOS 4.2.1 was the final release for your phone , so there is no baseband upgrade in future coming. This leaves your phone future unlocked on baseband 06.15.00 using UltraSn0w 1.2 . Read the tweet below by Iphone Dev member MuscleNerd .
If you are not sure which baseband you have , just goto Settings – General – About . Scroll at the bottom to see your modem baseband. You have to upgrade your baseband to 06.15.00 to jailbreak and unlock using UltraSn0w 1.2 . Follow the 06.15.00 baseband upgrade tutorial for details .
There are some GPS issues with the current unlock though . Dev Team is coming up with a solution for that with baseband downgrade method to be implemented on iOS 4.3.
To get more jailbreak and unlock update , don’t forget to Subscribe to our Emails and Follow us on Facebook.