Where are files copied when flashing?

Sorry for the newbie question but…
When flashing Jetson software, is everything installed on the SSD or are there some files installed on the PCB as firmware etc. I’m trying to understand how best to ship units in volume and want to know the fastest way of imaging Jetson. Ideally it is just imaging the SSD.

If you are speaking of an eMMC model of Jetson, then flash puts content on various partitions of the eMMC. If this is an SD card model of dev kit (not a third party carrier board), then boot content goes into the QSPI memory of the module, and rootfs goes to the SD card. In the case of booting external devices the flash still puts a lot of content on either eMMC partitions or QSPI. The “/boot” of the original media might also still be used. Directly or indirectly, the flash parameters for external media end up putting what is essentially a “pointer” to the SSD at some point during boot.

You cannot put everything on the SSD, it isn’t possible. Jetsons (and most embedded systems) do not have an actual BIOS. The functions which a BIOS would perform, including bringing up power rails and clocks in the right order, is instead performed based on software in the non-rootfs content. To put everything on the SSD isn’t much different than asking to put the BIOS on the SSD of a desktop PC. The part which would go on the external media, but which cannot be there on a Jetson, is the bootloader itself. Normally a BIOS would eventually transfer to a bootloader on external media, but you cannot do that (I suppose though you can consider chain loading to a bootloader on external media; however, that would not stop the requirement to have at least one bootloader on the Jetson itself).

1 Like

Hi S789,

Just as linuxdev said, there’s only rootfs on the SSD and all other boot contents would be on eMMC or QSPI.

Thanks for the replies.

It looks like it would be faster to install the Jetson specific files separate to the SSD specific files. Imaging the SSD separately should be much faster.

Is there an easy way to do this?

You could refer to the workflows in Linux_for_Tegra/tools/kernel_flash/README_initrd_flash.txt.

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.