The kernel package seems correct: $ find /lib/firmware/ -name overlay_map.dtb /lib/firmware/5.8.0-1006-raspi/device-tree/overlays/overlay_map.dtb
The kernel package seems correct: 5.8.0-1006- raspi/device- tree/overlays/ overlay_ map.dtb
$ find /lib/firmware/ -name overlay_map.dtb
/lib/firmware/