As the new iOS 5.1 beta 2 is now available for download for Developers only, we expect that this new update fixes the Battery issues and some other issues face by people on iPhone 4S and other iDevices. Battery issues are one of the most important issue on which Apple is working on.
So those of who you are waiting or willing to update to iOS 5.1 Beta 2 and planning to go back to iOS 5.x, after you have tested iOS 5.1 Beta2, So don’t ever think of updating to the new Beta because there is no way by which you can go back to iOS 5.x on iPhone 4S and iPad 2. You can go back on iPhone 4, iPod 4, iPod 3, iPhone 3GS and iPad 1. To go back to previous iOS 5.x version from this new Beta you need to used iFaith and save your SHSH Blobs+ AP Tickets in order to retain the firmware restoration.
As a personal opinion we would recommend that you people should stay away from this update, as there is no use to update, there is no method for the baseband preservation for this update and you cannot Jailbreak the firmware yet. We cannot even predict the Jailbreak or baseband preservation support coming soon.
Do remember that to save SHSH Blobs is necessary. If you will save your SHSH blobs, you will be able to downgrade back to iOS 5.x.x version with the upcoming update of Redsn0w. And the Untethered Jailbreak for iPhone 4 and old iDevies will be released on iOS 5.0.1 and iOS 5.0. So update to iOS 5.0.1 if you wish to update.