If it's an MB model (check the about screen) it might work. I'm currently restoring my 2g 32mb MB back down to 2.2.1. I found 2.2.1 on the felixbrun site, put the touch in DFU mode, pointed to the 2.2.1 file using the option click trick and so far, so good.
I have received some error messages during the restore process, but they're all related to incompatibility between some of my apps that were upgraded to 4.0 versions. Those weren't restored and hoping everything else works.
The restore just completed, and everything seems fine. A few apps won't work and guessing they are too new for 2.2.1, but I really just want my music to work again properly in my car. Overall the unit seems much snappier, just like the old days....