I have a Series 1 DTiVo. I replaced the original 40 GB with an 80 GB and then later added another 40 GB. The 80GB drive went bad and I used dd to copy it to a spare 160GB I had. Because I had already upgraded, it only used 80GB of the 160GB drive. At this point I had a 160GB A drive (of which only 80GB was being used) and a 40 GB B drive.
So, last week I started over. I put the two drives in a PC and got an image (SPs, Wishlists, no recordings). I copied that to a 40GB drive and then added the 160GB drive back. Now I have a 40GB A drive and a 160GB B drive. Since then, I'm having a strange problem. Some of my recordings are mixes of two or more programs. A recording will be fine when I check it one day and will be corrupt at a later date.
For example, last night's recording of Arrested Development was the Sci Fi Inside: Battlestar Galactica for the first 15 minutes or so. I recorded both, but they came on at different times. Also, I recorded A Goofy Movie for my daughter this weekend. She was watching it for the first 45 minutes or so while it recorded and there were no problems. When we went to play it back yesterday, it was mixed with segments from The Twilight Zone. Some Christmas programs I recorded last weekend were fine when I checked them mid-week. By the weekend, a message stating that there was no video signal or something appeared when I tried to play them.