Update dtb file on TX2 NX

[dat-tran-matternet]

Hi, I'm working with the new TX2 NX module. I assume it's similar to the TX2 modules. During development with device tree modification, I would like to just change the DTB of my system. I noticed that cboot is the one that's loading the DTB as seen from these log output:

[0001.382] I> Loading kernel-dtb from partition
[0001.386] I> Loading partition kernel-dtb at 0x80000000 from device(0x1)
[0001.404] I> Kernel_dtb @0x80000000

I assume if I can find which partition it is pointing to I can overwrite the DTB file with an updated one?

thanks

[dwalkes]

I've never tried it myself but the suggestions from #401 might be helpful.

[ichergui]

Hey @dat-tran-matternet
For your information, the DTB is signed then authenticated and loaded by cboot.
You can check the partition layout as well.

[dat-tran-matternet]

Awesome thanks!

[dat-tran-matternet]

Looking at the nvidia forum, I noticed people mention about the script "flash.sh" a lot to update dtb and cfg files. This script is not present in the tegraflash output from yocto. Is this script only available/usable if not using yocto? Just want to understand how yocto deviates from the official Jetson SDK/BSP. thanks

[dwalkes]

Is this script only available/usable if not using yocto?

Yes, it assumes you are using NVIDIAs L4T Ubuntu based distribution. It's replaced by the doflash.sh script and the instructions in https://github.com/OE4T/meta-tegra/wiki/Flashing-the-Jetson-Dev-Kit for OE4T/meta-tegra.

[ichergui]

Hey @dat-tran-matternet
Did you manage to update the DTB on the TX2 NX ?

[dat-tran-matternet]

I haven't tried the methods discussed here yet. I have been doing it the long way by flashing a new tegraflash image every time. Luckily I haven't needed to flash the dtb a lot yet. I'll update once I try it out. thanks