The newest version of the bootROM memory chip in Apple’s iPhone 3GS will prevent ‘jailbreaking’ the device in the same way as previous iPhones. This would stop users from ‘unlocking’ the device to install unapproved iPhone applications.
iBoot-359.3.2, which started to ship last week, isn’t susceptible to the 24kpwn exploit that’s used to jailbreak older versions of the iPhone – although this doesn’t mean a new vulnerability won’t be found in the future. [Source: iClarified.com]