JP5.0 and UEFI bootloader

JP5.0 release notes Whats New says “UEFI Bootloader”. Does that mean cboot and /boot/extlinux/extlinux.conf is no longer needed? Or do we still use cboot but with uefi bootloader as an alternative?

The release notes also says "Because UEFI boot is enabled in this release, the plugin manager is no longer supported. ". Does that mean we use cboot and not uefi boot, we can still use plugin manager?


Cboot has been deprecated and not in use anymore.

If you want to try similar things as plugin-manager, you can try to use device tree overlay.

There is example in


Thanks for confirming /boot/extlinux/extlinux.conf is no longer needed.

I have deleted from the rootfs and now with JP5.0 fails with

[   0.0301 ] Assuming zero filled SBK key : not reading 
[   0.0330 ] tegrahost_v2 --chip 0x19 0 --updatesigheader 1_kernel_tegra194-p2888-0001-p2822-0000_aligned_sigheader.dtb.encrypt 1_kernel_tegra194-p2888-0001-p2822-0000_aligned_sigheader.dtb.hash zerosbk
[   0.0371 ] 
[   0.0377 ] Signed file: /home/koi/workspace/xavier_34.1.0/Linux_for_Tegra/bootloader/temp_user_dir/kernel_tegra194-p2888-0001-p2822-0000_sigheader.dtb.encrypt Generate header for kernel_tegra194-p2888-0001-p2822-0000_sigheader.dtb.encrypt chip 0x19: add 0x5c9f4 to offset  0x8 in sig file Generate 16-byte-size-aligned base file for kernel_tegra194-p2888-0001-p2822-0000_sigheader.dtb.encrypt the signed file is /home/koi/workspace/xavier_34.1.0/Linux_for_Tegra/bootloader/temp_user_dir/kernel_tegra194-p2888-0001-p2822-0000_sigheader.dtb.encrypt
	populating kernel to rootfs... done.
	populating initrd to rootfs... done.
	populating kernel_tegra194-p2888-0001-p2822-0000.dtb to rootfs... done.
Making system.img... 
/home/koi/workspace/xavier_34.1.0/Linux_for_Tegra/rootfs/boot/extlinux/extlinux.conf is not found, exiting...

It didn’t even get to the hang stage that I mentioned in the other thread.

I didn’t mean /boot/extlinux/extlinux.conf is depreacated… I only said cboot is deprecated.

I thought extlinux.conf is only used by cboot. In JP 5.0, who is using extlinux.conf? On a normal linux with uefi, I have a /boot/efi directory but don’t have one on xavier. Usually uefi works with another bootloader such as grub, but what do we use in JP5.0 as bootloader?

I have not had a chance to look at the UEFI in JP5 yet, but UEFI is a “modular” system. It can be set up to load directly without something like extlinux.conf, and completely without a third party bootloader. Directly transferring execution to Linux after the platform is ready is one option, or using a bootloader is another option (e.g., UEFI can load U-Boot or GRUB or most any bootloader, but does not need to…it is a rather cool abstraction and far far more flexible than just a bootloader or CBoot). If extlinux.conf is used, then it is because someone wrote a wrapper to use the file with the same syntax as previous software did, but it would be executed by that abstract loader instead of whatever you are used to.

My understanding extlinux.conf is to be used to boot kernel/dtb from the /boot, but in JP 5, you can no longer boot kernel/dtb files from /boot as documented here:

  • Users will need to flash both the Kernel image as well as the Kernel DTB (Device Tree Blob) upon any modification.
  • Replacing the Kernel image and the Kernel DTB in /boot directory is not supported.

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