I already own a 128 GB nvme and have it built in my computer, but I also have bought a new one. Now I want to backup the nvme I already own with the new one I have bought
Cloning via flash.sh is only for the eMMC. You should use something separate for an NVMe. Can you put them on a separate computer? If so, then you could copy with dd. If not, perhaps you could remove the NVMe from the Jetson, set the Jetson up to boot normally, and then mount the NVMe back to the Jetson (in which case you can use dd on it since it won’t be in use as the rootfs). dd can go through ssh to copy to another machine if desired.