I'm getting error 22 when I use my custom restore ipsw and another (I think it was 1015) when I use the 4.1 IPSW from http://www.felixbruns.de/iPod/firmware/ .
I have "3354604965262-iphone-4.1.shsh" in ~/.shsh and TinyUmbrella does see that.
After you're done with the restore and get the error message go to TU and click "kick device out of recovery".
After that the iphone should boot up with 4.1 installed.
After you're done with the restore and get the error message go to TU and click "kick device out of recovery".
After that the iphone should boot up with 4.1 installed.