May I ask why this is not suitable for factory production?
You could pre-build an modified UEFI image with default boot order set to NVMe. (Initrd flash boot order - #26 by WayneWWW)
Just replace UEFI image in Linux_for_Tegra/bootloader/uefi_jetson.bin.
They should be the same. You could use the downloaded Jetpack SDK from SDKM. The path is as following indicated in SDKM.
Have you tried Workflow 7: Initrd Massflash for massflash?
and what’s your result of Workflow 10, does the following issue still exist?
l4t_initrd_flash_internal.sh: line 735: Linux_for_Tegra/tools/kernel_flash/initrdflashimgmap.txt: No such file or directory