Thank you.
After "*Power*-button, keep it pressed, and press *7* *3* *Stop*" the buttons are working.
But it looks like that this has to done every time after Libreelec has started - if I keep the TV switched on and restart Libreelec the buttons do not work anymore until the sequence above is entered again.
Is Libreelec sending something to the TV at startup which causes that the buttons do not work ? If yes, can I change this ?