Happily your SHSH blobs on the newest iOS firmware can be saved using the updated version of TinyUmbrella — TinyUmbrella 5.11.00.
Using the latest RedSn0w version, your device can be downgraded to iOS 5.0.1 using your previously saved SHSH blobs. For the future downgrade your need to save your SHSH blobs.
|Download TinyUmbrella 5.11.00|
The updated version of TinyUmbrella can be downloaded from here.