So, I tried to keep the top 0x400 bytes and just replace the bottom section with a “signed and encrypted” DTB file. Tegraboot compiled about something. This is what I put in my Readme file:
Currently this is how I update the DTB:
For the Jetson Nano, the root DTS file is located here:
<install>/nvidia_sdk/JetPack_4.2_Linux_P3448/Linux_for_Tegra/sources/hardware/nvidia/platform/t210/porg/kernel-dts
The current Jetson Nano rev uses **tegra210-p3448-0000-p3449-0000-a02.dts**
Modify that file and the files it includes (DTSI). When you build the kernel it
will build the DTS files into DTB files. The resulting DTB file is located here
(assuming you use the **build** directory above)
<install>/nvidia_sdk/JetPack_4.2_Linux_P3448/Linux_for_Tegra/sources/kernel/kernel-4.9/build/arch/arm64/boot/dts
Now comes the hard part. The DTB file needs to be placed into a partition header
and signed/encrypted. The only way I've found to do this is to copy the DTB file
here:
<install>/nvidia_sdk/JetPack_4.2_Linux_P3448/Linux_for_Tegra/kernel/dtb
Then run:
sudo ./create-jetson-nano-sd-card-image.sh -o sd-blob.img -s 4G -r 200
This will create an IMG file that can be programmed into an SD card or the internal
eMMC on the actual SOM. In the process of creating the IMG file it will take
the DTB file and place the signed copy here:
<install>/nvidia_sdk/JetPack_4.2_Linux_P3448/Linux_for_Tegra/bootloader/signed/tegra210-p3448-0000-p3449-0000-a02.dtb.encryptQ
Pull the SD card out of the Nano and put into your Linux machine (share the USB into the VM).
Now the following in the **bootloader/signed** directory.
sudo dd if=tegra210-p3448-0000-p3449-0000-a02.dtb.encrypt of=/dev/sdx10
This will program the DTB file into the partition. Put the SD card back in the
Nano and reboot.