TinyUmbrella has been updated to version
5.10.11 5.10.12 with a new feature that allows for users to save their iPhone’s BBTicket, which could aid in downgrading A5-powered devices — the iPhone 4S, iPad 2, and new iPad — in the future. Currently, this freshly released version of TinyUmbrella supports the iPhone 4, iPhone 4 (CDMA), and iPhone 4S.
TinyUmbrella is a utility for Windows and OS X that allows users to downgrade their iPhone, iPod touch, iPad, or Apple TV software to a previous firmware version using saved SHSH blobs. Apple has changed the way that SHSH blobs function in iOS 5 and later, however, so newer iOS devices will no longer be able to use this method to downgrade.