manually copying kernel image (no jetpack) ?

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX1
1

Hello,

In all examples of building and install kernel I see that jetpack is used (./flash script).
Is it possible instead to manually copy the image into the correct folder ? (I try to build kernel in target)

Thank you,
ran

2

In earlier releases this was possible. In more recent releases this is no longer possible. Some access is required before U-Boot is reached, and those earlier stages do not have the ability to read ext4 partitions. Combine this with additions which are going in for the purpose of securing boot with signatures, and the binary partitions themselves must be signed.

You can go through steps to sign content and then use dd to put that in place (provided the new partition fits in the old space), but simple copy (even by dd instead of as a file) would result in a failure to boot. Some URLs you might be interested in:
[url]https://devtalk.nvidia.com/default/topic/1035668/jetson-tx2/how-to-disable-dtb-encryption-of-l4t-28-2/post/5295198/#5295198[/url]
[url]https://devtalk.nvidia.com/default/topic/1044313/jetson-tx2/in-system-update-of-propretiary-nvidia-bootloaders/post/5298969/#5298969[/url]
[url]https://devtalk.nvidia.com/default/topic/1045462/jetson-tx2/-tx2-can-not-flash-tx2-any-more/post/5306008/#5306008[/url]

3

Hi,

Eventually a simple copy did work , and we use latest jetpack 3.3.
All we had to do is to copy to emmc path (/media/emmc/…/boot)
So, why did you think it shouldn’t work ?

Thanks

4

If you copied the rootfs it is a different story than if other partitions are modified. The rootfs is not signed. Other partitions are now sometimes signed. If a copy works, then it implies the copy didn’t modify any of the other signed partitions. The kernel image is no longer used from the rootfs “/boot” partition of newer releases (or at least the earlier boot stages don’t use this partition), and so if you replaced a kernel via “/boot” file copy, then you should check if the kernel is actually being used (it depends on which release you use…actually I think R28.1 is when planning for those changes started, but most of R28.1 can probably be copied directly…I use R28.2 on my TX1 and so many copies will no longer work).