Notcom has updated TinyUmbrella to version 5.10.15 including some bug fixes related to first generation iPad for backing up the SHSH blobs. Prior to this, there were a couple of errors occurring while saving the SHSH blobs on iPad. TinyUmbrella 5.10.15 works smoothly removing those glitches to save SHSH blobs.
Apple has already pushed iOS 5.1.1, with in 1 or 2 days, Apple will stop signing the older firmware, so it is highly recommended to save SHSH blobs and BBTicket for future use. Though currently, there is no way to downgrade to older firmware but these SHSH blobs and BBtickets will help to downgrade in future.
You can download TinyUmbrella 5.10.15 for Mac / Windows from the link below and follow the guide here to save SHSH blobs and BBTickets.