The boot mode of jetson AGX Orin board

[meng.li]

Hi Nvidia exports,

I flash my AGX Orin board with link Jetson AGX Orin Developer Kit User Guide - Two Ways to Set Up Software | NVIDIA Developer. And then the board boots up normally.
But I have below questions

1. I want to know where is the Image burned into, emmc, sd card, flash or other storage devices?
2. If there any docs to guide me setup the expected boot mode, and burn the image into expected storage device, and confirm the boot mode is the expected one?

thanks,
Limeng

[linuxdev]

An AGX Orin has eMMC. Jetsons do not have an actual BIOS, but they do have the equivalent in software. Much of the flash is about creating a number of partitions in the eMMC for booting, including what would function equivalently to the BIOS. A normal flash puts a single partition in eMMC to become the o/s image. Normally that is “/dev/mmcblk0p1”.

To boot to an SD card or NVMe one uses an initial ramdisk (initrd). The command line initrd flash (in the tools subdirectory of “Linux_for_Tegra/”) has a README file and the script for flashing to these alternate devices. Much would still go into the eMMC, but that eMMC would then point to the initrd instead of mmcblk0p1; the initrd performs a pivot root of “/” on the initrd to “/” on a partition of the NVMe or SD card partition.