It appears that Apple is attempting to block those that jailbreak their iPhone/iPad. Those which have jailbroken their iPad or iPhone with greenpois0n appear to triggering a "jailbreak check" which was added to iOS back in version 4.0.
"There is a problem with the configuration of your iPhone," the error message in iBooks 1.2.1 reads. "Please restore with iTunes and reinstall iBooks."
Hacker comex of the iPhone Dev Team has explained on twitter how the new jailbreak check works...
"It seems that before opening a DRMed book, 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."
It appears that the motive of Apple is to protect potential piracy of eBooks, but this security measure is also preventing legally purchase electronic books from being accessed. A fix has already been developed by comex and will be incorporated into the next jailbreak for iOS.
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