HDHomerun code needs brought up to date
The HDHomerun code is very ancient. It is based on Silicon Dust's old libhdhomerun source code, with some custom additions thrown in.
The current libhdhomerun source is very different, so porting the changes over is going not going to be a simple task, but needs done. Most of the important sourcecode is in a custom hdhomerun_mythconfig.cpp - it simply uses the rest of the libhdhomerunlibrary calls.
There is also a wiki page showing a good patch and makefile modification at http://wiki.linuxmce.org/index.php/Silicondust_HDHomeRun#Comcast_Qam that helps with QAM stations. This would be a good time to also investigate and apply this patch in our own code.