It should just be a matter of opening Settings, then Video parameters and checking Video & Audio is selected. Don't remember from web interface what it was.
I can second this question. I put my 2.5" hdd inside the thing, but it just cannot see it.
I tried to erase its partition table, format with fat, ntfs, both GPT and MBR.. No way to have it detected.
Btw, I just updated my N6200-16EH to 20160707 fw (from the device itself) without problems.
EDIT: I wonder how 2016060718 compares http://forum.videon.spb.ru/viewtopic.php?f=24&t=5930&start=3285#p71056