I would build my own kernel image if I knew how. I work on a different ARM SoC (Marvell CN10K), but the boot method is somewhat different, and I'm not sure how OpenSUSE ARM kernel images are set up and built. On that SoC I have the root filesystem EXT4 image on the eMMC device and use tftp to load a kernel into U-Boot and use the booti command to boot it, but this is also a buildroot setup.