Apple has reportedly tweaked the way its iPhone is coded in an effort to freeze out users who jailbreak the company’s handsets.

It’s understood that when Apple ships new iPhone 3GS phones, they’ll come loaded with a “bootrom” that defends against the 24kpwn exploit used by the Dev-Team and individuals to jailbreak artificial restrictions built into the popular smartphone.

Indeed, the Dev-Team warned iPhone users last week to hang fire on installing the latest iPhone OS.

More recently, the group’s hacker MuscleNerd has confirmed that for the time being a normal jailbreak of the phone would be impossible, following the loss of the 24kpwn exploit.

Users jailbreak their handsets in order to install unsigned Apple Apps on their iPhone. The Cupertino-based company has watched world dog enjoy the exploit for the best part of this year.

But the next batch of iPhone 3GS units to arrive in-store are expected to come with code that prevents the jailbreak.

All of which will probably lead to another exploit being discovered, although with each Apple patch, the jailbreaks have turned from a gush to a trickle.