Origin for each line in root.init.mk from check-in 7a1e7f4a58:

7a1e7f4a58 2019-10-21        arcade: root: fsck bootfs
7a1e7f4a58 2019-10-21        arcade: 	echo "MRC:$@> Mount root R/W."
7a1e7f4a58 2019-10-21        arcade: 	mount -uo rw /
7a1e7f4a58 2019-10-21        arcade: 	umount -a