Notcom has updated TinyUmbrella to version 5.10.09 which fixes the bugs when saving SHSH blobs of AppleTV 2 and AppleTV 3.
Earlier, TinyUmbrella 5.10.08 was released to save SHSH Blobs of iPhone, iPod Touch, iPad (includes support also for New iPad/iPad3) running on iOS 5.1.
TinyUmbrella is required to downgrade over device to a lower firmware.With the release of iOS 5.1 Apple has closed signing in Window for iOS 5.0.1 so it is important that you save SHSH blobs.

i0n1c has demonstrated untethered jailbreak on iOS 5.1
and iPhone Dev Team has also uploaded screenshots of Jailbreak New iPad / iPad 3 On iOS 5.1, hence, so you must save the SHSH blobs of your device running on iOS 5.1 using TinyUmbrella 5.10.09 as untethered jailbreak will be released soon.
Download TinyUmbrella 5.10.09 for Windows and Mac OS X
Download TinyUmbrella 5.10.09 for Windows
Download TinyUmbrella 5.10.09 for Mac OS X