If you want to make sure that you have the file you have 2 choice
1 open tiny umbrella then click on your device, in the middle of the page there is a white box that is all your shah saved for that device.
2) Open terminal and write cp /Users/Mike/.shsh
inside write ls and see what it shows you.
Here is how to downgrade your Ios.
1) Open Tiny umbrella and click on start TSS server
2) Open terminal and type ping gs.apple.com (it should answer 127.0.0.1
3) Open iTunes and go to your device and press (keep pressing) Option
4) While option is pressed click on restore, and select the Official firmware for the IOS you want to downgrade to for the good device
Exemple Ipad2 GSM 4.3.3
Let itunes do the rest.