I'm on a Mac & I've got the 4.3.3 IPSW. Have tried straight 'option click & point at IPSW' on restore button in iTunes 10.5 beta and iTunes 10.3 plus tried this while phone is in DFU mode - get the message 'this device not eligible for requested build'.
Tried running TinyUmbrella while doing this and it seems to get past the 'checking with Apple' phase, but then stops with either a '1600' or '20' error message... but I don't really understand what TinyUmbrella is doing, or if I'm using it correctly, and the shsh blobs are not stored for this phone.
If anyone has any suggestions I'd appreciate it. TIA.