Thank you for your reply stack!
I believe that I have tried this. However, I have packed down the player to be returned to Futeko. Not due to this issue. But that the player interferes in the HDMI ARC passthrough sound between my LG TV and my Pioneer sourround receiver. Really strange. When the Q10 Pro was connected to the receiver with the HDMI cable passthrough sound did not work. And when I disconnected the HDMI cable from the Q10 Pro passthrough sound worked. This is not a problem with my old media player, Dune HD TV303D.
Not so strange at all: HDMI-CEC is a system-bus type of protocol: Any device on a combined TV and/or AMP HDMI setup may and in fact will communicate with each other. It does not matter on which port they are connected on the TV or AMP. So bad behavior of just one specific device may affect communication and correct working for the total HDMI-CEC setup regardless the port being connected to. HDMI-CEC in fact is a very powerful standard but often implemented in a very poor (too simple) way.
This is a known and reported problem. It is presumable fixable via a FW update. My own setup is workable as long as I switch on Q10 Pro last and turn it off first (as it jeopardizes HDMI-CEC only when ON). Using a HDMI-CEC blocker will by-pass any kind of HDMI-CEC related problems.
http://www.satmarkt.com/product_info.php?info=p2645_hdmi-cec-sperre--adapter-fuer-unterbrechung-des-cec-steuersignals.html
Obviously made due to many problems with incorrect/incompatible implementations.
I am getting the impression Himedia is moving to Android 7 TV/Leanback to amongst others tackle this problem. Recent Android TV/Leanback OS versions have support for HDMI-CEC build-in. But even with this never have seen a 100% correct implementation on any Android based media player myself yet. The most important feature is a ON/OFF Master setting to avoid the need for a HDMI CEC blocker (=sperre in German).