I've been meaning to try this for a while. I live in SoCal and am on Charter. I have a Moxi (by Diego) HD DVR, it has a firewire port on the back, along with some USB ports.
In Nov, Charter pushed the 3.2 firmware to the Moxi, which I believe allowed access to the FW port.
Yesterday, I hooked up my HTPC (Intel MacMini) to the Firewire port, got iRecord and the apple Firewire toolkit.
Connected with no issues, all works, including channel changing from the software.
I then proceeded to scan every channel I get by recording a stream and recording.
Get this: I can record AND playback ANY SINGLE CHANNEL I get. This includes premium HD channels and other premium content. I hope this lasts, because I'm sure eventually they will set the play once tag. I can also record the streams playing back form the DVR.
This kicks butt. I can't believe I waited until yesterday to try this (laziness?)
The MacMini can record the streams and play back through VLC with absolutely no problems. I recorded and edited some HD music videos last night, and they look great.