I've recorded stuff that was on the 4K channels before, and here's what happened to me. I could see the 4K recording in my list of recordings on ALL TVs in the house, but I could only play it back on the C61K client. If I tried to play it back on any of the other clients or on the HR54 it wouldn't play. I forget what the error message said. I believe in the list of recordings the 4K shows also had a "universal no" (circle with diagonal line through it) next to them on all non-C61K clients if I remember correctly.