I have a hearing impaired listening device (Simolio SM-823D) connected to my system with Toslink. When I try to use the device with my Roku Ultra I do not get any audio. My Roku is connected to my TV via HDMI, my A/V receiver is connected to my Tivo box via HDMI(ARC). Thanks for any help!
I think where I'd start is looking at your avr to see if there is a setting to turn on/off the passing of optical via hdmi. As I understand your post, content from your roku (hdmi) is not being sent from your avr toslink output. You get audio from your roku otherwise I take it, to connected speakers?