Postscript: systemd-hwdb-update.service calls "systemd-hwdb update", which ignores any changes made in /etc/udev/hwdb.d/*.hwdb
It reverts any changes to hwdb.bin which have been made by "udevadm-hwdb --update"
Therefore the workaround command sequence required to ensure that changes made in /etc/udev/hwdb.d/*.hwdb are reflected in hwdb.bin *and persist* is:
systemctl mask systemd-hwdb-update.serviceudevadm hwdb --updateudevadm trigger /dev/input/eventXXSuggestion for a fix:
1. Deprecate systemd-hwdb
2. Modify udevadm help text and man page to show the "hwdb --update" command option again
