Sat Jun 23 19:28:52 EDT 2018

TRM Booting Procedure

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.