On my series 2 TiVo branded unit, I upgraded my single 80GB drive to two 160GB drives. The original IDE cable is 80 wire, and the new dual drive cable is 40 wire. Everything worked fine for many months, and then one day the TiVo got stuck in an endless loop trying to reboot. It would only get as far as "almost there" before it would start over at "welcome powering up." I put the original 80GB hard drive back in the system, using the 40 wire dual drive cable, but it didn't work. It would not even get to the "almost there" screen; it was stuck on "welcome. powering up." I tried connecting the drive in different positions on the cable, but there was no change. I tried two other 40 wire cables and those didn't work. Then I tried the original 80 wire IDE cable with the original 80GB hard drive. Works perfectly now. Is this a known issue or just some kind of weird fluke? Did TiVo's upgraded software somehow mess up compatibility with the older 40 wire cables? I am going to the store later to buy an 80 wire dual drive cable, to see if I can get my expanded storage space back. Does it matter which end of the cable is attached to the TiVo, versus attached to the drive, or can I reverse positions? Thanks for any insight.