Few weeks back iOS 4.3.3 was released to fix the Jailbreakme exploit which was used to Jailbreak iPad 2 on iOS 4.3.3. To save the SHSH for he iOS 4.3.3 and iOS 4.3.4 you needed to use Tiny Umbrella and used to unchecked the option of uncheck request SHSH from Cydia in order to save the SHSH Blobs.

So today Cydia showed up with SHSH Blobs for iOS 4.3.4.

Before Cydia was said to update the SHSH after some time, after the release of every new iOS. See if your SHSH for iOS 4.3.4 are showing up in Cydia or not. If not then use Tiny Umbrella and save them.