[tvandyck7]

Well it depends on what you want to do. If you want to go back to the 2.0.1 or the old 2.1, do as Blazingwolf said with the SBF file. Since 2.1 has been rooted, you could just root and flash a new 2.1 rom. The only thing is that there probably currently are more/better roms with 2.0.1 or the old 2.1. It's really not as difficult as it sounds. After rooting, it is as easy as can be.