Help- I spoke with level 3 tech support at Direct TV. They have it in their documentation and on their forum that firmware revisions made last quarter of 2013, make the 24 not compatible with the am 21. Local channels will not display in the guide nor will listing be refreshed from their uplink it in Richmond Ind. For Cincinnati market. I have an old Panasonic box, a mpeg 2 high def being used as sd. Thus box is acting strange requiring reboot after bing turned off. I think it thermal related possibly to memory. I need an intergrated preferably dvr. My understanding is even Tivos just have a pass thru. Not an actual Atsc tuner like the 20. I will buy a 24, but I believe it won't support the an 21. This is straight from level three DTV. What us the truth on this??? I think Direct Tv intentionally has disabled use if the am21. I know fir a fact that on the 20, they eliminated the orig. Design to obtain both primary and secondary city guide info in latest 20 firmware revision. I was old that Corporate policy was to phase out any OTA support period.