Notcom has updated TinyUmbrella to version 5.00.09 which fixes iPad2 CDMA restores bug.

TU 5.00.09 fixes another bug with iPad2 CDMA restores. Sorry folks. It was a rare case that I missed. .09 should fix your ipad2 woes

Earlier,he had released TinyUmbrella 5.00.08.

Change log of 5.00.08 is as follows-

iPad 2 GSM/CDMA will restore the currently signed baseband so 10xx errors won’t happen (This will cease to work once apple stops signing the current 4.3.x firmware’s baseband)
Optional iPhone 4 baseband update is now available to those that are officially unlocked. NOTE: iPhone baseband can ONLY be restore/updated to a baseband that apple is currently signing. END OF STORY
Added 4.3.5, 4.3.4 support
Fixed a nasty baseband request error for ipad 2 cdma.

Saving of SHSH blobs is required if you want to downgrade to older firmware.

However, downgrade of iOS 5 will not be possible as Apple is closing saving of SHSH blobs.Hence, you should save SHSH blobs.

Download TinyUmbrella 5.00.09

TinyUmbrella 5.00.09 for Windows

TinyUmbrella 5.00.09 for Mac OS X