The game of cat and mouse still continues between Apple and a group of hackers.
Apple are now stating that the iPhone 3GS units that they are now shipping are actually Jailbreak proof. Some hackers that specialize in iPhone 3GS Jailbreaks are saying that the well known 24pwn exploit is no longer viable.
The reason for that is that Apple have started shipping iPhone 3Gs models with a new bootrom which is capable of resisting the hacking technique. The bootrom used in mobile phones is a computer chip that actually checks the phones software when the phone is switched on, and makes certain that the device has not been tampered with. Source – pcworld.com