You can try to copy the DTBs (and overlays) from /lib/firmware/5.4.0-<xyz>-raspi/device-tree/broadcom/ to /run/mnt/ubuntu-seed after refreshing the kernel snap.
You can try to copy the DTBs (and overlays) from /lib/firmware/ 5.4.0-< xyz>-raspi/ device- tree/broadcom/ to /run/mnt/ ubuntu- seed after refreshing the kernel snap.