MMC/SD Cards or eMMC/ eSD devices may hold a FAT file system which ROM Code is able to read and process. The image used by the booting procedure is taken from a specific booting file named “MLO”. This file has to be located in the root directory on an active primary partition of type FAT12/16 or FAT32. I wonder. Does the bootloader work at all without the .dtb? Let's try.