OK - let's try not using the hdhomerun filter just to see if we get a channel listing. Go into the sd2xmltv addon settings and turn off hdhomerun and turn on file based channel filter. Set the number of days to 0. Rerun the internal grabber in tvheadend.
-- this won't add program data - but should create a file called filter.cfg in your userdata/addon_data/tools.module.sd2xmltv folder.