I’m trying to make just two small gpio changes to the stock dev board device tree. I’ve tried the following things:
First I tried decompile the dtb file tegra186-quill-p3310-1000-c03-00-base.dtb and then I made my changes to the .dtc and then recompiled and put it on the the TX2 filesystem. Then I added the FDT entry to /boot/extlinux/extlinux.conf file. My gpio changes worked but I no longer had an ethernet interface available. I also tried just using the unmodified .dtb file but it also had no ethernet.
So then I looked in jetson-tx2.conf in linux4tegra 28.1 package and saw that it was configured to use tegra186-a02-bpmp-quill-p3310-1000-a00-00-te770d-ucm2.dtb so I tried decompiling that and making my changes but when I booted using that dtb the tegra halts and fails to boot. I also tried booting with the tegra186-a02-bpmp-quill-p3310-1000-a00-00-te770d-ucm2.dtb unmodified but same result.
So what am I supposed to do? How can I extract the actual dtb file from the working image on the TX2? Why does it seem like there is a mismatch between the dtb that is already built into the image and the ones you provide in the source?
Thank you for your response.