The cat-and-mouse game between Apple and a cadre of hackers continues, as Apple is reportedly now shipping iPhone 3GS units that are jailbreak-proof. Several hackers specializing in iPhone 3GS jailbreaks are saying that the well-known 24kpwn exploit is no longer viable, because Apple is now shipping iPhone 3GS models with a new bootrom that can resist the hacking technique, according to iClarified.