Thanks for your reply, sorry - missed that step, I’m now using the correct device name, however getting the same error.
sudo ./tools/backup_restore/l4t_backup_restore.sh -e nvme0n1 -b recomputer-orin-industrial
It seems like something in the script is deleting the content of bootloader/secureflash.xml which is causing the error. Replacing it with the copy from the image for the industrial J4011 and running the command empties the file out and gives the error again.