Just a quick answer to the first question from user with actual product that I see while I get to work on other questions...
Hi DSDHead,
1. There's a toggle in the system's sound options (pull down the notification shade to show access button) that toggles the multifunction port between line out and coaxial digital output. The toggle has to be in the Coaxial setting for digital output to work.
2. I was told that the noise may be caused by WiFi interference at the 2.4GHz band, which intermodulates into audible frequencies. Could you turn off the WiFi radio if it is on to see if this is the case? If the headphone output works fine, it is also recommendable to use the headphone output for line duty because you can see even from the specs that they are evenly matched for line output performance, with the headphone output having (inaudibly) slightly worse distortion but better THD.
3. The official feedback channel is via
service@hiby.com although I'll also be watching this thread like a hawk now that product is reaching backers' hands