I've got the optical cable in place now.

It is definitely sending 5.1 sound to the amp. However the amp is labelling it all as Dolby Digital Surround 5.1, whatever app/source it is coming from.

With HDMI/ARC I was getting Dolby Atmos and the like passed through to the amp, which of course isn't going to happen over the optical link.

So I guess I might end up plugging the Apple TV and Bluray into the amp, losing all the nice LG input switching UI

Also, I haven't done any significant testing of lip sync yet, which I'm guessing could easily be an issue too without the HDMI/CEC/ARC "magic".

I wish I could go back to a month ago, where it was all just working correctly like it had for the last 14 months.

*sigh*