Apple has opened a new chapter in its campaign against hackers with a feature that prevents jailbroken iDevices from accessing iBooks.

According to the Social Apples blog, iPhones and iPads running the latest iOS firmware contain a “jailbreak check” that automatically detects when the devices have been unlocked using the greenpois0n jailbreak kit. Jailbroken devices that attempt to load content using the iBooks application – even legally acquired e-books – display an error message that reads: “There is a problem with the configuration of your iPhone. Please restore with iTunes and reinstall iBooks.”

“Comex,” a hacker with the iPhone Dev Team, said in a Twitter post that “iBooks drops an improperly signed binary, tries to execute it, and if it works concludes that the device is jailbroken and refuses to open the book.”

Apple finds itself in the same predicament as Sony, maker of the PlayStation 3 game console. Both companies want to control what software customers can run on their consoles to boost sales of authorized titles and prevent potential piracy. Unlike Sony, which hauled more than 100 jailbreakers into federal court, Apple is largely barred from taking legal action, thanks to a move last year by the US Copyright Office exempting jailbreaking from the Digital Millennium Copyright Act.

The report comes on the heels of a recent announcement that greenpois0n is now able to apply an untethered jailbreak to second-generation AppleTVs. Untethered jailbreaks are the preferred method of unshackling iDevices since the change persists even after they are rebooted. It's still not clear exactly what can be done with a jailbroken AppleTV. One option is to run NitoTV, a user interface that loads playlists and displays weather forecasts. It's automatically installed when greenpois0n is run. ®