No Sound from HDMI Input

[GJC]

I have a LG OLED55C7T TV, with the latest software.

I replaced my Topfield 2400 PVR (1080P) with a Beyonwiz U4 (2160P) on HDMI 1.  I get picture but could not get any sound to the TV via HDMI.  I tried both SD and HD channels. All show video, but no audio.

I checked all volume and mute setting on the TV and on the Beyonwiz.

I checked the TV firmware is the latest available release.

I tried all of the HDMI inputs and 3 different HDMI cables with no luck. I tried other devices in these TV HDMI inputs and all worked properly (i.e. had sound).

I re-flashed the U4 Firmware and went through the setup again. Still no change.

I tried setting the TV to factory defaults and setting it up again, but still no sound.

I connected an optical cable from the S/PDIF output to my amplifier and sound works.

I tried plugging the U4 into another TV via HDMI and it works properly - both video and sound.

But the combination of the U4 and the LG TV does not work. So, I'm convinced that its software or a setting on either device that is mismatched. The LG work perfectly with all other HDMI devices that I connected to it (BlueRay Player, Topfield PVR, Nexus Player, Canon 5dMk4 Camera) but I can't get it work with the Beyonwiz U4.  The U4 works fine via HDMI to another TV.  So why won't they work together?  What settings should I try changing?