Create tar rootfs, use whole SD card size for rootfs.

configs/olinuxino_defconfig

 BR2_LINUX_KERNEL_INTREE_DTS_NAME="imx23-olinuxino"
 BR2_PACKAGE_FFMPEG=y
 BR2_PACKAGE_FFMPEG_SWSCALE=y
-BR2_TARGET_ROOTFS_EXT2=y
-# BR2_TARGET_ROOTFS_TAR is not set
 BR2_TARGET_UBOOT=y
 BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
 BR2_TARGET_UBOOT_PATCH="$(BR2_EXTERNAL)/board/olinuxino/u-boot"

flash.sh

 	echo Could not find a suitable bootstream!
 fi
 
-echo Writing root filesystem
-sudo dd if=output/images/rootfs.ext2 of="$1"2 bs=512
+if [ -e output/images/rootfs.tar ] ; then
+	echo Creating root filesystem
+	sudo mkfs.ext4 "$1"2 -L rootfs
+
+	echo Mounting root filesystem
+	sudo mkdir -p /media/rootfs
+	sudo mount "$1"2 /media/rootfs
+
+	echo Copying root filesystem
+	sudo tar xfp output/images/rootfs.tar -C /media/rootfs
+else
+	echo Writing root filesystem
+	sudo dd if=output/images/rootfs.ext2 of="$1"2 bs=512
+fi
 
 echo Synchronising changes to disk
 sudo sync