Rock - thanks for the heads up, downloaded 4.2.1. From your note looks like another firmware update imminent as well. Hopefully Tivo and ATV will be better behaved or I may go down the a new HDMI 2.1 cable between my Lyngdorf and C9 - george
I've no idea what's in this update, only that it's software and the one coming up will be more HDMI focused.
A 2.1 cable is only recommended when the chain is all 2.1 from: source>processor>display
And that's just best practice, it's not actually essential if you cables are good enough. I think these zeskit cables are meant to be good for 2.1 sources without being silly money but there are others.