kumquat-buildroot/board/pc/genimage-efi.cfg

image efi-part.vfat {
	vfat {
		file EFI {
			image = "efi-part/EFI"
		}

		file bzImage {
			image = "bzImage"
		}
	}

	size = 16352K # 16MB - 32KB
}

image disk.img {
	hdimage {
		partition-table-type = "gpt"
	}

	partition boot {
		image = "efi-part.vfat"
		partition-type-uuid = U
		offset = 32K
		bootable = true
	}

	partition root {
		partition-type-uuid = 44479540-f297-41b2-9af7-d131d5f0458a
		partition-uuid = UUID_TMP
		image = "rootfs.ext2"
	}
}