Thanks... Unfortunately, I won't be able to test much in the next couple of days. Busy elsewhere... 
In the meantime, can I leave you with some other findings related to HdmiCec to look at or think about?
Firstly, about the HDMI logfile (hdmicec.log)... Some RXdata, which can be represented as plain text, is not readable because of non-printable characters.
I've included a sample below. (The data of command 32 should be displayed as "ger"). Could it be converted before writing to logfile?
hdmicec.log 1.49KB
1 downloads
Also, some of the received commands are not logged with their name (like the message A0 in the attached logfiile).
It's not important, but would be nice and easier to read. Maybe a few more common command names can be added. (especially broadcast messages)
About the infamous fixed physical address - I stronly suggest to remove this non-compliant option. It has no added value, only creates problems.
Besides, it is a violation of the HDMI-CEC standard. As for testing with a spoofed CEC address, one can always use the HDMItest plugin.
Next... On the Hdmi CEC setings page, the physical address is hidden when CEC is set to Disable. In earlier days it was always visible.
Can this be reverted? It should always be visible. The physical address allocation takes place, regardless if CEC feature are used or not!
Moving on... When the box is booted, the various Receiver models have different concepts for dealing with the initial physical address.
Some boxes will start with physical address to F.F.F.F, which is the correct behaviour.
But some boxes keep their previous (!) address instead. This behaviour is most questionable.
Is there any way to control these boxes to make them behave compliant?
Can the address be set to F.F.F.F on reboot? Or is this something hardcoded in the drivers?
Almost done now... The screen "Information" - "About" also shows the CEC address. But strangely, only if a fixed address is used.
Can it be changed to show the actual physical address? And could additionally be mentionend there, if the physical address has been assigned through the allocation process? (as opposed to the (invalid) self-assigned address)
Finally, considering the above, the receiver should not send any CEC commands prior to registration on the CEC-bus. (aka physical address allocation)
Hopefully the issues will be discussed and addressed by the PLi team. 
I consider these basics.
Once in place, the next step could be about scenarios, options, presets, and how to fully take advantage of the CEC capabilities with different TV types, sound systems, etc.
And btw. Often referenced in the forum is HDMI Specification 1.3. I think, the better version to consider is 1.4b (2011).
Edited by Stan, 1 September 2023 - 21:29.
