C120 air mouse back and volume buttons

  • I have an C120 air mouse remote. It has a 2.4GHz dongle, no IR functions, keyboard on the back and navigation buttons and mouse button on the front. (link)
    My system is a DELL Wyse thin client with an Intel CPU, running LibreELEC 12.0.2 and Kodi 21.2.0.

    The remote works fine in Kodi in mouse mode and in regular mode, except 3 buttons: volume up/down and back.

    In LibreELEC, I have identified these events linked to the remote:
    * event6: the 3 missing keys (and only those)
    * event7: all working buttons (navigation and the backside keyboard)
    * event8: mouse movement and buttons (when remote is in mouse mode)

    Although they produce the expected output with evtest, the 3 event6 buttons do not give any code in the Kodi keymap editor.

    Output of cat /proc/bus/input/devices for the ones linked to the remote is below.

    Any suggestions?

    (note: this is a different remote from my earlier questions. I got this one hoping it would work since it is a bit more simple, but alas.)