The company will update the software making it impossible to downgrade the firmware, says the iPhone Dev Team, the group behind many successful jailbreaks and unlocks.
Members of the iPhone Dev Team saw the change in a recent unlocked developer's version of iOS 5.
For current iPhones/iPod Touch, if you want to restore your device to an earlier firmware, you can use SHSH blobs which timestamp specific times and allow for third-party apps to restore the device.
In the new iOS, the group says "Apple will re-assign your phone a new SHSH blob each time your reboot your device in jailbreak mode, making saved blobs irrelevant since Apple can just reject ones that were saved."
Written by: Andre Yoskowitz @ 27 Jun 2011 16:29