buildroot/board/zynqmp/genimage.cfg

image boot.vfat {
	vfat {
		files = {
			"boot.bin",
			"u-boot.itb",
			"system.dtb",
			"Image"
		}
		file extlinux/extlinux.conf {
			image = extlinux.conf
		}
	}

	size = 32M
}

image sdcard.img {
	hdimage {
	}

	partition boot {
		partition-type = 0xC
		bootable = "true"
		image = "boot.vfat"
	}

	partition rootfs {
		partition-type = 0x83
		image = "rootfs.ext4"
	}
}