I can confirm the THR Tivo remote's Slow-Mo button is not functional with an HR24. In fact, the LiveTV button doesn't do anything either and I couldn't find anywhere that the Clear button worked (certainly didn't work when I wanted it to). And, the Tivo remote doesn't have an Exit key which is helpful when operating an HR. The big Tivo button takes you to the main menu in the HR but a second press of the Tivo button takes you back to live TV - not into the Now Playing list like it would on a Tivo. To get to the NP list on the HR you have to press Tivo, down arrow twice, select and select again - whew. So, overall the THR remote isn't very good for the HR - although it can do the basics - somewhat clumsily.