iPhone Dev Team Provides Details About Downgrading From iOS 6 to iOS 5.x

iPhone Dev team has just published a post titled “Blob-o-riffic”, which provides details about downgrading from iOS 6 to iOS 5.x.x.

iPhone Dev team has warned that iPhone 4S, iPad 3 (and some iPad 2) users won’t be able to downgrade from iOS 6 to iOS 5.1.1 once Apple stops signing iOS 5.1.1 and will be stuck until a jailbreak for iOS 6 is released.

Dev team also noted that there are some serious deficiencies in the iOS 5.x.x restore process which are permanently exploitable in the iOS firmware file, which will allow users to re-restore their iOS device to iOS 5.x even after Apple stops signing the iOS 5.1.1 firmware. iPhone Dev team will be releasing a new version of Redsn0w that will include this new re-restore functionality.

The Dev team has listed down the scenarios for different iOS devices.

1. A4 devices and 3GS will always be downgradable (and jailbreakable) due to limera1n.  The tethered iOS6 jailbreak for those devices (and untethered for old-bootrom 3GS) will be out when Cydia and other important pieces are all working properly
2. iPad2 owners who have both 4.x blobs and 5.x blobs will always be able to downgrade to those versions, even once you come up to 6.0 and the 5.1.1 window closes (don’t do that yet though!).  You need both 4.x and 5.x blobs to qualify for the downgrade even if you only wish to downgrade to 5.x
3. iPad3, i4S (and iPad2 owners who don’t satisfy #2) will always be able to RE-restore the current 5.x OS that’s already on their device.  So if you’re at 5.1.1 when the window closes (and you’ve saved your blobs), you’ll always be able to RE-restore to 5.1.1 again.  This makes the 5.1.1 jailbreak a lot less fragile — you don’t have to worry about messing up your install with funky extensions or getting into a boot loop, because you can always RE-restore from 5.1.1 to 5.1.1 again (or from 5.0.1 to 5.0.1 again, etc).  But once you fall off the 5.x train by restoring to 6.x, you’ll be stuck there until the next jailbreak.

It basically means that iPhone 4 and iPhone 3GS users will able to downgrade if they have the SHSH blobs using Redsn0w. They will also release a new version of Redsn0w that allows them to jailbreak (tethered) iOS 6 once the issues with Cydia and modules like PreferenceLoader are fixed.

iPad 2 users will be able to downgrade to iOS 5.x only if they have both the iOS 4.x and iOS 5.x blobs.

iPad 3, iPhone 4S and iPad 2 (who don’t have iOS 4.x and iOS 5.x blobs) users who do not upgrade to iOS 6 will be able to re-restore to the current iOS 5.x firmware that is installed on their device. The ability to re-restore will make it a little less stressful to stay on jailbroken iOS 5.x.

iPhone Dev team hasn’t provided any further updates on iOS 6 jailbreak, we’ll let you know if we have any further updates.

So without wasting any time take a backup of SHSH blobs before Apple stops signing iOS 5.1.1. You can follow this guide to save the SHSH blobs using TinyUmbrella.

[via Dev team blog]

Posted by iPhoneHacks on Sep 19, 2012 - iphonehacks.com