Origin for each line in bootfs.init.mk from check-in 7a1e7f4a58:
7a1e7f4a58 2019-10-21 1: bootfs: fsck 7a1e7f4a58 2019-10-21 2: echo "MRC:$@> Checking whether we need /boot mounted." 7a1e7f4a58 2019-10-21 3: mount -vadr | grep -q ' /boot$$' && mount -r /boot || true