Corrupted device tree file replacement at boot loader

Hi

I have Replaced the dtb file in the mmc
It was corrupted so the device is not booting
But I have the backup of the working dtb file in mmc
Does any one know the commands for copying the dtb and replacing the corrupted one

the corrupted file is in
ls mmc 0 /boot
the actual back of working file is in
ls mmc 0 /home/ubuntu
I need to know how to copy the file from this location to boot and removing the corrupted file in boot

please suggest

Changing DTB depends on which L4T release. Is this R28.1? Or is it from prior to R28.1 (R28.1 is the point when instructions change)?