If you are not familiar with jailbreaking, and the tools involved, TinyUmbrella is a great tool that allows you to easily save your device’s SHSH blobs, allowing some devices on certain firmwares to be restored from a 3rd party server. The creator of this software, @notcom, has released an update, which is compatible with Apple’s latest iOS devices.
TinyUmbrella now has support for saving 5.1 SHSH for Apple TV 3 and the iPad 3 (all versions). As of now we still cannot restore them but we are working on getting that working from a bunch of angles. I’ll let you know more when I do.
If you are at all interested in jailbreaking, it is a good idea to have your SHSH blobs saved on the Cydia server. It will allow you to restore some devices back to an earlier firmware, where Apple does not. As mentioned above, the newest devices cannot be restored this way yet, and any device cannot restore to an earlier 5.0 firmware. Restoring back to anything below iOS 5.0 (presuming the device supports it) can be restored to an earlier firmware, using the TinyUmbrella tool.
Download the Mac version here: TinyUmbrella [OSX]
Download the Windows version here: TinyUmbrella [WIN]