In message 9e4733910808030557t269eb1fye375d66f8bb7f200@mail.gmail.com you wrote:
No, no, no. The DTB *must not* be included with the U-Boot image. It shall always be kept separate so we canupdate it independently - otherwise you lose a lot of advantages.
A DTB is only about 8K. I was thinking that a user supplied one would override the one contained inside uboot.
Then you have to take special care that the DTB is flash sector aligned and sufficiently padded - this extra effort and introduces a new, avoidable single point of failure. If the DTB can be at any flash location, you can for example have a fall-back version which is used to bring up U-Boot in a minimal configuration for recovery mode if the new DTB fails to work.
Best regards,
Wolfgang Denk