Apple has begun to ship new iPhone 3GS units with an updated boot ROM, breaking the exploit commonly used to jailbreak the device. iClarified reports that the new ROM—iBoot-359.3.2—is not vulnerable to the “24kpwn” exploit, and began shipping last week. According to a Twitter post from “MuscleNerd,” this is the first time in the history of the iPhone and iPod touch that hackers have seen Apple update the boot ROM in the middle of a product cycle. Apple has in the past attempted to block jailbreaking through software updates, but this strategy has been less and less effective as the platform has matured, with most recent software updates being jailbroken either hours after, or in some cases, prior to, their official release.
Update: A member of the iPhone Dev-Team, a group that publishes tools to jailbreak the iPhone and iPod touch, has clarified that the new boot ROM does not in fact prevent jailbreaking, but instead makes it more difficult to reboot a jailbroken iPhone 3GS once it’s been turned on. According to Wired, without the 24kpwn exploit, jailbreaking will still be possible, but all jailbroken units with the new boot ROM will need to be tethered to a computer in order to turn on if turned off or if they run out of battery life.