Jetson Xavier NX as QSPI and boots from it and hence with the NVME driver in the bootloader, we can now only flash QSPI and NVME and load from NVME without touching emmc at all.
But things are different on Jetson AGX Xavier where there is no QSPI and boots from emmc. So we need to have minimum thing flashe to emmc, so that bootloader running from emmc can then load the rootfs, kernel, dtb, etc from NVME.
Please use the new flashing tool for this, refer to “Flashing using initrd” section of the documentation (also there is a README in the BSP which has many examples) https://docs.nvidia.com/jetson/archives/l4t-archived/l4t-3261/index.html#page/Tegra%20Linux%20Driver%20Package%20Development%20Guide/flashing.html#wwpID0E0PI0HA
Also i announce to you and the forum that we will be releasing support for flashing external media like NVME/USB connected to Jetson Xavier NX or Jetson AGX Xavier from SDKM itself soon!