repo init -u https://source.codeaurora.org/external/imx/imx-manifest -b imx-linux-sumo -m imx-4.14.98-2.1.0.xml
Here do you want to download the build images to your board? If yes, you can use the uuu tool to download, but you need to do some modify toward your board and build images. Details you can see the samples under demo images.
The steps download uboot, kernel ,dts and rootfs you can see.
About how to make all these images to .sdcard file, we also do not know how to.
do we have another way make all images to single file for factory production?
Yes, but not build in Standalone build. The build step you have to follow our use guide.
Which board and BSP are you using?