You can make as many dupes as you like, for different TiVos, from the same source drive. All will work. The one caveat is that all of the boxes except the on the source drive came from to begin with will report a "hardware error", and will not work at all, at first. This is due to the drive containing the hardware address (TSN) of the original system it came from and the other boxes not matching that address. The menus work though, and once you go to the CADE option (Clear and Delete Everything), and once that process finishes (can take hours), it will work fine.