There is finally a good news for those who have been beseeching for downgrading iPhone 4S, iPad 2, and iPad 3 firmware. iPhone Dev Team has finally squashed all the issues related to A5/A5X downgrading process.
If you have inadvertently upgraded your device firmware and want to revert to older one to retain untethered jailbreak, the upcoming Redsn0w 0.9.11b1 utility will allow jailbreakers to downgrade between versions of iOS 5.x (for instance, iOS 5.1 to iOS 5.0.1) and restore to the older firmware without iTunes. But yes, it will only work if you have already saved SHSH blob files for the firmware you want to restore to.
A new set of options (under Extras -> Even More-> Restore) will be made available – Local Restore and Remote Restore. Local blobs will use those SHSH blobs that are saved into your machine and Remote option will allow you to use SHSH blobs that are saved in Cydia. In order to enable Remote option, you have to connect your device in DFU mode. Another feature has been added into redsn0w that stitches the blobs on the fly.
On ETA upfront, we would advise everyone to stay calm. The team is hard at work and they will announce updated redsn0w as soon as they can. We will update you about its release along with the tutorial guides, just follow @JAlLBREAKS on twitter or on Facebook.
[Update #1]: iPhone Dev Team has released Redsn0w that lets you downgrade iPhone 4S, iPad and iPad 3 from iOS 5.1.1 to iOS 5.1 and iOS 5.0.1