Hi,
Actually, only few partitions are on the NVMe. So you can directly use below command.
img2simg /dev/nvme0n1p1 system.img.ext → this is create the backup image
blkdiscard /dev/nvme0n1p1
simg2img system.img.ext /dev/nvme0n1p1 → this is to apply the backup image to partition.
If you want to use initrd_flash to flash this cloned out image to other device’s NVMe. You can just replace the system.img.ext during the workflow of initrd_flash. There should be one step that you can see this image inside the folder.