Notcom has just released a new TinyUmbrella update (v4.33.00) which is now capable of saving iOS 4.3.3 SHSH blobs for iPhone 4(GSM)/3GS, iPod Touch 4G/3G, iPad 2/1 and iOS 4.2.8 SHSH blobs for Verizon iPhone 4. For those who don't know, an SHSH blob is a code which iTunes returns after singing your ECID from Apple servers and it is used to verify the version of iOS you are running!
Whenever you upgrade the firmware of your iDevice, you must save your SHSH blobs before Apple closes the SHSH window. If you will not save your SHSH blobs for the specified firmware, you will not be able to downgrade to that specific firmware in future once Apple releases a new iOS version.
To save iOS 4.3.3 or iOS 4.2.8 SHSH blobs, just connect your iDevice to your PC or Mac and launch TinyUmbrella software. Click on your iDevice name from the side-panel followed by a click on Save SHSH button. To save SHSH blobs from Cydia or Apple servers locally, you must have an active internet connection. Also to run TinyUmbrella without any JAVA error, install latest version of JDK and JRE from here.