meta-digi/meta-digi-dey/recipes-digi/swu-images/files/image_template_rdiff_mmc

                {
                    type = "rdiff_image";
                    filename = "@@SWUPDATE_RDIFF_ROOTFS_DELTA_FILE_NAME@@";
                    device = "##DEV##";
                    properties: {
                        rdiffbase = ["/dev/rdiff_source_rootfs"];
                    };
                }