[noggin]

I was able to get the FW update just now :-)

I'm having some general issues with Kodi Leia RC2 though.  Here are the tests I've performed this evening.

Fire TV stick plugged into Denon Receiver 4K input.General GUI :
TV displays 3840x2160 60Hz

Amazon Prime :
Playing Grand Tour 1080p version.  TV reports 3840x2160 @ 25Hz.
Playing Grand Tour UHD stream, TV shows 3840x2160 24Hz HDR10.  Looks great.

Grand Tour S1 was shot 2160/24p - Series 2 onwards was 2160/25p. Series 2 should be output 2160/25p or 2160/50p. 2160/24p is not perfect.

iPlayer :
I can watch Dynasties in UHD.  TV reports 2840x2160 60Hz HDR HLG (but colours are dull).

Dynasties UHD on iPlayer is 2160/25p HLG Rec 2020. It should be output 2160/50p Rec 2020 SDR or HLG (HLG is backwards compatible with SDR)

Very few iPlayer platforms apart from Smart TV internal players are correctly signalling HLG...