In order to save space on the SPI flash, SquashFS + JFFS2 should be used.
Partition Content Offset Size (byte)
mtd0 uboot-bin 0 0x58000 (360448)
uboot-env 0x58000 0x8000
mtd1 dtb 0x60000 0x4000 (16kB)
mtd2 kernel 0x64000 0x400000 (4MB)
mtd3 rootfs 0x464000 0x4FC000 (4.98MB)