I have an iPhone 3GS on 3.1. I'm very sure that I have my ECID SHSH on file with Cydia because I remember being in Cydia before I upgraded and and wondered what it meant when it said "ECID SHSH" on file.

I have changed the hosts file per Saurik's instuctions and when I go to downgrade to 3.0 I get an error message from itunes saying

*The iPhone "iPhone" could not be restored. An unknown error occurred (20).* You're posts don't really mention anything about this code and I've tried the it a few times only to get this message and the phone left in recovery mode.

Please I would love to downgrade again to enjoy the jailbreak benefits, what shall I do?