Falsh kernel-dtb

In the following forum, I have a few questions. I need your help and the system version I use is R35.1. Thank you.

  1. There are two ways to update the device tree. One is to delete the file “/boot/extlinux/extlinux. conf” and then use the command to refresh the device tree (sudo./flash - r - k kernel dtb jet son xavier nx devkit emmc mmcblk0p1). After deleting the “extlinux. conf” kernel boot file, how does the kernel automatically choose which kernel to start with?
  2. What is the difference between the two commands? When I use the “- r” parameter, I occasionally need to reconfigure the system initialization, but after the configuration, my own files in the system are not lost.
sudo ./flash -r -k kernel-dtb jetson-xavier-nx-devkit-emmc mmcblk0p1
sudo ./flash -k kernel-dtb jetson-xavier-nx-devkit-emmc mmcblk0p1
  1. No, you don’t need to totally delete the whole extlinux.conf. You just need to remove one line from it.

  2. “-r” means re-use the “system.img” created before. If your BSP does not have “system.img” created in prior flash, then running -r will give you error message.

OK, I see. If I choose the second way to update the device tree, do I need to delete the FDT entries in the “extlinux. conf” file first, and then copy the compiled new device tree to the “/boot/dtb” directory.

What is “second way” and what is “first way”?

It is mentioned in the forum that the device tree is updated without using the flash tool

I don’t want to directly answer this question as this is really not that hard and you can figure it out by yourself…

Just some hints here…

“FDT” in extlinux indicates a path where UEFI can read dtb from rootfs. Which means you don’t need to reflash to update kernel dtb. Just replace that file.

And flash command with “-r -k xxxx” is to flash the dtb into a partition which is not rootfs.

Okay, I see. Thank you!!

that’s means:

1, flash the new.dtb into /boot
2. replace /boot/dtb/x.dtb with new.dtb

FDT /boot/dtb/x.dtb

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