It is widely known that there is not any untethered jailbreak for the A5 devices that run the 5.1 Update.
However, a new bug was found at the APticket of the 5.1 Update that allows users to downgrade to 5.0.1 (That there is an untethered jailbreak).
The 5.1 Update has only some minor changes, especially for the iOS security. Specifically:
1. Delete photos from the Photo Stream
2. Japanese for Siri
3. Camera Shortcut always visible from the Lock Screen
4. Camera Face Detection
5. Minor other Chacges
As you can see, there aren’t any great changes.
So, if you would like an untethered jailbreak, for now, you need to have the 5.0.1 version.
Apple stopped signing iOS 5 SHSH Blobs so that even if you have saved them, you cannot restore back to previous iOS 5 Versions. The only change you got is this bug. This bug was found by iH8sn0w. This is what he tweeted:
Found a loophole in Apple’s apticket system. Restored my iPad 2 to 5.0.1 from 5.1. Works on all A5 devices. 🙂
(( The tweet can be found here… ))
Thus, these are indeed good news. Note that A4 devices can already downgrade via a custom IPSW from iFaith or Redsn0w.
We hope that there will be a public release of the Bug.