No audio on SDI A or the HDMI in? Double check your DUAL-HD setting!
 

If you happen upon that your SDI A input or HDMI in has no audio being input despite the audio source being SDI/HDMI, double check your "DUAL-HD VIEWING" setting and make sure it's "SIDE BY SIDE" or "TOP/BOTTOM." If you leave the mode on "*a|B," SDI A and the HDMI input will be muted in single stream recording mode. DUAL HD settings should ideally not matter when single stream recording is activated and a single input is present, but apparently DUAL HD settings stick and can bite you in the butt if you aren't on top of making sure it's set correctly.

Just a forewarning to any Odyssey owners about this bug.