Hi adam.gulyas,
What’s the Jetpack version in use?
What’s the SKU of your module?
SKU0 should be Orin NX rather than Orin Nano.
You can simply put this module onto the devkit board(p3768) and run the following command to check.
$ cat /etc/nv_boot_control.conf
Are you developing this custom carrier board?
Only SKU5 has the SD slot on the module.
Do you connect a NVMe SSD and you want to boot from it?
For the custom carrier board, you have to use custom BSP package with the custom board config. They should be customized according to the design of your board.
In addition, you can refer to <Linux_for_Tegra>/tools/kernel_flash/README_initrd_flash.txt to use initrd flash script to flash.