TinyUmbrella has simply been updated to version 4.30.05 to fully support iOS 4.3.1 devices are: iPhone 4/3GS, iPad iPad 2, iPod Touch 4G/3G. Currently Verizon iPhone is not supported.
TinyUmbrella allows you to save your iPhone SHSH files and is available for Mac and Windows. Furthermore Recovery Fix is also available for Windows and Mac, to correct the beginning to restore.
You can find instructions on how to save your SHSH Blobs below. You need to do this to ensure you can downgrade your iDevice to a lower firmware versions in the future.
Download TinyUmbrella for Mac
Download TinyUmbrella for Windows