iPhone Dev Team have published a video demonstration on using the Ultrasn0w unlocking solution tool to unlock iPhone 3GS (3G S). iPhone Dev Team claims Ultrasn0w uses the at+xlog crash as an injection vector of our unlocking payload, and it does so on the iPhone 3GS in exactly the same way as on the iPhone 3G. Together with 24Kpwn exploit found in iPhone 3GS bootrom, ultrasn0w will be able to be used on the iPhone 3GS for unlockers, without any modifications whatsoever.
NOTE: DO NOT UPGRADE TO 3.1 YET IF YOU WANT THIS UNLOCK.
A brief demonstration of the iPhone Dev Team’s unlock for the new iPhone 3G S.
Before using ultrasnow to unlock iPhone 3GS, it’s recommended to backup the personalize 3.0 firmware bundle.
A warning though is that ultrasn0w injection vector will be lost if user update to upcoming iPhone OS software 3.1 using the official Apple IPSW, which also updates the baseband. Until a tool is released that allows user to update the firmware without updating the baseband, any upgrade to firmware OS 3.1 will break the unlock.