I kept getting lost trying to map my Tivo remote's buttons to the MX-850. I tried a paper list, which didn't help. I needed a layout diagram that shows the physical relationship of the hard buttons.
The solution was to photograph both remotes, blank out the LCD, add grid lines for LCD labels, and colored lines for the button mapping:
Each line and text label is in it's own layer. I suppose I could have used Illustrator or a similar program where the lines would be separate objects..
I used the Tivo[117] code set, and had to learn Thumbs Down and Live TV.