IPhone – Restore an iPhone from iCloud backup of newer iOS version

icloudiphonerestore

I have an iCloud backup from an iPhone running iOS 8.3. Now, I'd like to restore another iPhone from this backup. The problem is that the other iPhone is running iOS 8.2 (this iPhone cannot be updated to 8.3 as I need it to run this very version).

I found some guides on the internet explaining how to do a downgrade from a beta version (I didn't find anything about downgrading from non-beta versions). But they are about downgrading from a major release to another major release (eg: iOS 8 to iOS 7).

My thought is that, unlike the iTunes backup, iCloud backup saves only information about the data on your iPhone (a list of all installed apps, a list of all downloaded music, movies, etc.) and when you restore from an iCloud backup, it will just re-download this media from iTunes and the App Store.

I didn't just try this yet as I don't know whether some data in iCloud may get corrupted by restoring to an older version.

Does anybody have any experience with this kind of thing?

Best Answer

You cannot downgrade unless one of the following is true:

  • Apple is still signing installations of the previous version of the OS to which you wish to downgrade, or
  • Your phone is jailbroken, you have saved your SHSH blob from the prior version, and you have a way to run a replay attack with that SHSH blob to trick the device into believing Apple is still signing that version.

You can determine whether a particular version of iOS is currently being signed for a given device on ipsw.me. Simply change 8.2 in the URL to the version you want to check, such as 8.0 or 8.3.

This list of updates, from the same website, shows when Apple starts and stops signing a given version.

In your case, 8.2 stopped being signed on 5/4/15. Therefore it is no longer possible to downgrade. Generally the window is about a month or so after a new version is released.

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