image_types: format rootB as ext4 with the appropriate label
image_types: format rootB as ext4 with the appropriate label

Signed-off-by: Petros Angelatos <5ae4506022d2e10a17fe64868893c6af9c21e85f@gmail.com>

resin-os/meta-resin,resin-os/meta-resin,resin-os/meta-resin,resin-os/meta-resin