Yesterday, iPhone Dev team released Redsn0w 0.9.11b1 that allowed users to downgrade their iPhone 4S and iPad 2 from iOS 5.1.1 or iOS 5.1 to iOS 5.0.1.
However, they had inadvertently missed out including support for iOS 5.0.1 (build 9A406) – the tweaked version of iOS 5.0.1 that Apple had released to fix the “Unknown SIM”, “No SIM card installed” problem.
iPhone Dev team has just released Redsn0w 0.9.11b2 to add support for iOS 5.0.1 (build 9A406).
Until yesterday, it was possible to downgrade only iPhone 3GS, iPhone 4, iPad 1, iPod touch 4G and iPod touch 3G from iOS 5.1 to iOS 5.0.1 using the SHSH blobs saved using TinyUmbrella.
But with Redsn0w 0.9.11b1/0.9.11b1 users can downgrade their iPhone 4S and iPad 2 from iOS 5.1.1 or iOS 5.1 to iOS 5.0.1 if they’ve saved the SHSH blobs for iOS 5.0.1.
Downgrading to iOS 5.0.1 will allow users to perform the untethered jailbreak using Absinthe jailbreak. Unfortunately, users who have recently purchased their iOS device that come pre-installed with iOS 5.1 won’t be able to downgrade as personalized SHSH blobs is required for the downgrade process. So even though Redsn0w supports the new iPad, it will allow users to downgrade from iOS 5.1.1 to iOS 5.1 as it came pre-installed with iOS 5.1 (which means that they could only save SHSH blobs for iOS 5.1).
As always, let us know how it goes.