TinyUmbrella is the tiny (see what i did there?) program that allows you to save SHSH blobs so that your iOS device remains jailbreakable over time and you also have the option to downgrade to the respective fimware whose SHSH blobs you have saved. Without a doubt, TinyUmbrella is an essential software in the jailbreaking game, and now that has been updated to version 4.30.05 which adds iOS 4.3.1 support for iPhone 3GS, iPhone 4, iPad 1, iPad 2, iPod touch 3G / 4G. Previously, TinyUmbrella was updated with support for Apple TV 4.3.1 software.
TinyUmbrella 4.30.05 release was announced by notcom on Twitter:
TinyUmbrella with iOS 4.3.1 support released. 4.30.05 will grab your 4.3.1 SHSH. Incidentally, it looks like 4.3 is closed. (still checking)
Download TinyUmbrella 4.30.5 for Windows and Mac
Download TinyUmbrella 4.30.05 for Windows
Download TinyUmbrella 4.30.05 for Mac