TinyUmbrella version of 4.21.03 and 4.21.04 was released to fix bugs to save the SHSH blobs of iOS 4.3 b2.In the version of 4.21.04 a bug was found regarding saving SHSH on the iPad.
To fix this issue TinyUmbrella 4.21.05 is being released.
Notcom the person behind TinyUmbrella said in his blog-
I’ve just added iOS 4.3b2 support. For those of you with Apple Developer accounts, this means you can save your SHSH’s for that version and restore to it permanently. Keep me posted of any issues. I’m still working on my next big contribution to the scene…
EDIT: Ok so I had a FEW bugs. 4.21.05 should work peachy