hello larry.ciummo,
please note that, kernel and dtb were signed and encrypted for security process.
you should generate these with flash scripts locally with --no-flash option enabled.
for example,
$ sudo ./flash.sh -r --no-flash -k kernel jetson-xavier mmcblk0p1
after that, you may copy this binary to your remote target, and using dd commands to update the partition without flashing.
you may also refer to similar discussion thread, Topic 148122 for reference,
thanks