Denon X4700H ARC and HDMI handshake issues

Got myself a new Denon X4700H AV amplifier. It can power 9 speakers and process upto 11 channels with the use of an external 2-channel power amplifier. Wanted to share the HDMI and ARC handshaking problem with this set. I could not find any YouTube videos on this issue, it&a different issue from the HDM1 2.1 bug which does not allow 4K@120Hz gaming, that has been reported quite extensively. My set&serial number is higher than 70,001 and according to Denon, the HDMI 2.1 gaming console bug has been fixed for these newer units. Hope the video is useful. Cheers!