[malvinas2]

I have an Intel NUC controlling Kodi Libreelec with an universal remote. 
The added HDMI-CEC adapter shall power on and off the attached AVR and TV via CEC, but it shall NOT control the volume of the AVR. 
The problem is, that just the front panel of the receiver shows volume changes, but no OSD is shown in Kodi. That's why I don't want the volume signals to be forwarded to the AVR. 
(alternative question: Is it possible to display the 'normal' volume icon in Kodi?)

(I am not using passthrough)

On-screen volume display when using HDMI-CEC for volume?
CEC support for volume control

[malvinas2]

I solved the problem using the network standby function of my avr instead of CEC. 
The AV receiver I am using is Yamaha RX-V685 and offers a SOAP API which allows to control the device, like turning it on, off, adjust volume etc. 
A simple "curl http://192.168.5.219/YamahaExtendedContr...r?power=on" does the job. 


More info: 
Sending commands to Yamaha AV Receiver
Yamaha MusicCast HTTP simplified API for ControlSystems

There is also a python automation library available:
Automation Library for Yamaha receivers

[Jogee]

I know that you solved your problem, but I thought I would offer some extra information in case you find it useful.

Have you tried CEC controlling the TV instead of the AVR?

I have an older Yamaha AVR setup with CEC (see my sig) only on my TV and AVR.  I don't have CEC on the computer.  I have it setup that turning on my TV will turn on my AVR, and turning off the TV will turn off the AVR.  I also have the TV setup to control the volume of the AVR -- when I press the vol up/down on the TV remote there is an overlay displayed shown on the TV indicating I'm making a change.  Changing volume using the AVR remote doesn't show anything on screen.

It does depend on the TV having the options to power up or down the AVR though through CEC, and if the NUC powering on the TV will chain power up the AVR.