<span class="tb_red">'''NOTE:'''</span>
If you are flashing a fresh Pi OS to NVME ssd, you have to [[#Enable PCIe]] after booting the device; if you are COPY or CLONE an old system Pi OS from SD card to NVME ssd, and you have already enabled pcie in the old Pi OS in advance, then you don't need to do enable pcie operation again!
==Set NVMe early in the boot order==