usb recovery - any way to flash only kernel / dtbs?

Is there any way to recover just the kernel & DTB files over USB, without wiping out the rest of the file system?
I’m currently trying to recover from a possibly bad compile.

Have already tried the full flash, but it seems that my parallels work environment isn’t supported and fails for some reason; any suggestions on the best way to bring the system back up? (serial console is also not working in case anyone asks that; an oscilloscope trace proved that the baud rates are off on my board for some unknown reason.)

Normally the kernel is just a file in “/boot”. Same with a “.dtb” file if this is specified from extlinux.conf. Flash has an ability to flash by partition ID (e.g., root partition is “APP”), but I’m not sure if this works for file copy (the “-k” option can be used in fastboot to name a kernel partition…how this works with U-Boot I don’t know).

Something which easily works (but takes a lot of time) is to clone. A clone can be loopback mounted on your host and kernel and DTB files can be copied to the clone, then you can flash with the clone instead of a newly generated image…you’d end up with an exact match of the original file system (other than the edits). The actual TX2 clone command is this:

Although the TK1 clone command is different the information here is otherwise relevant: