boot.txt

setenv fdt_addr 0x42000000
setenv fdt_file mt8167-coral.dtb

echo Loading image...
ext2load mmc ${mmcdev}:${boot_partition} ${kerneladdr} boot.img

# Load base device tree.
echo Loading device tree...
ext2load mmc ${mmcdev}:${boot_partition} ${fdt_addr} ${fdt_file}
fdt addr ${fdt_addr}
fdt resize

# Load overlays to arbitrary address beyond fdt location (will apply them later).
setexpr fdtovaddr ${fdt_addr} + F0000

# Overlay memory config for EVT2
if test "${evt2_board}" -eq 1; then
	if ext2load mmc ${mmcdev}:${boot_partition} ${fdtovaddr} coral-evt2.dtbo && fdt apply ${fdtovaddr}; then
		echo Loaded EVT2 config
	else
		echo Overlay EVT2 config failed
		ext2load mmc ${mmcdev}:${boot_partition} ${fdt_addr} ${fdt_file}
	fi
fi

# Parse overlays.txt and apply individual overlays.
if ext2load mmc ${mmcdev}:${boot_partition} ${fdtovaddr} overlays.txt && env import -t ${fdtovaddr} ${filesize} && test -n ${overlay}; then
	echo Loaded overlay.txt: ${overlay}
	for ov in ${overlay}; do
		if ext2load mmc ${mmcdev}:${boot_partition} ${fdtovaddr} ${ov}.dtbo && fdt apply ${fdtovaddr}; then
			echo Overlay of ${ov} successful
		else
			echo Overlay failed, reverting to original device tree
			ext2load mmc ${mmcdev}:${boot_partition} ${fdt_addr} ${fdt_file}
			bootm ${kerneladdr} - ${fdt_addr}
		fi
	done
fi

bootm ${kerneladdr} - ${fdt_addr}