Is it just those channels? Or all channels have no DVR function? Do you get an error message >> Like ERROR 024?
Odd issue indeed, try checking every channel ( I know its time consuming ) and see what you get. Have you had any other issues besides this lately?
I recently replaced the hard drive. I got the image of the hard drive from another 721.
I think you found your problem
Why would that cause an issue? Aren't all 721's the same?
GO DAWGS!