Disabling CEC in system/input/peripherals/cec settings should avoid this (but will stop CEC remote control from working).
You may be able to disable some of the options there to avoid it.
I think really we want this libCEC included: use system audio mode request instead of power on to start AVR reliable by gdachs · Pull Request #208 · Pulse-Eight/libcec · GitHub
You would try a Milhouse nightly which does include that - does it work better for you?
LibreELEC Testbuilds for RaspberryPi (Kodi 17.0)
Disabling CEC in system/input/peripherals/cec settings should avoid this (but will stop CEC remote control from working).
You may be able to disable some of the options there to avoid it.I think really we want this libCEC included: use system audio mode request instead of power on to start AVR reliable by gdachs · Pull Request #208 · Pulse-Eight/libcec · GitHub
You would try a Milhouse nightly which does include that - does it work better for you?
LibreELEC Testbuilds for RaspberryPi (Kodi 17.0)
Already disabled all in CEC settings 
Will try with new SD card those nightly builds, THX.
To be sure you can add to config.txt:
hdmi_ignore_cec=1
which will mean CEC messages cannot occur. Assuming that is the problem then I can't think of anything LE is doing to cause HDMI devices to switch inputs or power on.
it seems that everything works as it should, TV's cec power on avr when you switch to it's hdmi port, that's how it should work.
If you want to keep avr powered off I assume you don't want use it to play audio, so why not link it directly to an HDMI port on the TV? Maybe I did not understand...
Inviato dal mio Nexus 5X utilizzando Tapatalk
Understood, I think disable cec as suggested by popcornmix is the only solution even if it seems strange that no one has encountered your problem. Keep in mind that the cec standards is not really "standard" and some manufacturers use different specifications. Make some tests, such as raspberry pi connected directly to TV and check if LibreELEC settings are met (power on/off by cec) so you can begin to understand what does not work. Hope this help.
Inviato dal mio Nexus 5X utilizzando Tapatalk
Is it possible to power on a Kodi box with a CEC remote? Official remote might be broken, looking for other ways to boot up the box while not having to pull the power.
Tronsmart S95.
Is it possible to power on a Kodi box with a CEC remote? Official remote might be broken, looking for other ways to boot up the box while not having to pull the power.Tronsmart S95.
Have you looked into WOL (wake on LAN)? Your box and router will need to support it... and you will need some know-how. I'm sure there will be separated threads for WOL. There are phone apps for WOL.
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I'm probably six months too late but have you considered changing settings of Marantz AVR to disable CEC? This is not ideal if you control the amp volume with your TV remote.
I understand this doesn't explain the difference in operation between OE and LE.
