I am about to upgrade my Tivo to a 1.5TB hard drive. I need to do it because my Tivo drive (inside the box) is failing. Yes, I tested the HD. The Tivo als has a 1/2TB expander. I want to save the shows. I know if I have one drive I could (reimage) backup and restore the information on the new drive. Is it possible to do with a 2 drive system?? If Yes, how?