When you go to edit favorites, one is listed as FX and the other is FXHD. While they have the same channel number, there is an internal code that is different, and the DVR uses that. IF you have both enabled, the first one in channel # order (the first one after 247) is the HD channel.
While I'm pretty sure it says FXHD in the banner, you can tell the difference with SD content in that the HD channel version is clearer -- it's really 640x480 effectively uncompressed, versus the SD channel which is 480x480 compressed to death.
OK, I did edit the favorites, for all the new HD channels, and deselected the old SD version.
So now the DVR will know to only use the new HD channel to record my season pass, right?
It's confusing to me, in that if I manually input the channel number, I end up at the old SD version (at least on some that I have tried, like the food network, FX, etc). If I channel surf, I end up at the HD channel (248-1), because that's what's in my favorites. I haven't seen a method to tell the DVR which one to use.