question about cboot ?

1.Does xavier cboot support boot sign linux image feature ? to get in cboot cmd line ? there any cboot document user guide ?

  1. If you are talking about the signature of secure boot, then the answer is yes, cboot supports it.

  2. As I know, cboot does not have cmd line. May I know what is the purpose of cmdline? Are you talking about the kernel command line?

  3. No, currently we only release the source code and a readme file for compilation. L4T documentation has some introduction to cboot.

  1. My meaning is when building linux kernel, the linux kernel is signed and cboot will check the signature and booting linux kernel. Did cboot support it ?
  2. Does cboot support like fastboot or u-boot, we can get in its command line interface ?
    And thanks your response.

Hi boyi_liao,

  1. Yes, cboot does support this feature and current kernel and kernel dtb are already signed before flash.

  2. If you are talking about the kernel command line, it is actually inside the board config. For example, p2771-0000.conf.common is the board config for TX2.

cboot would handle those cmdline in “partner/common/lib/linuxboot/cmdline.c” and add this to dtb by “common/lib/linuxboot/dtb_update.c”.

Hi WayneWWWW:

  1. Did this feature default enable or we have to modify for this feature ?

  2. The kernel you are talking about is cboot little kernel, not linux kernel right ? And how to get in it ?
    maybe CTRL+C or something in booting ? and the same configure file for Xavier ?

Thanks your response.


  1. This feature is enabled by default on both TX2/Xavier platform.

  2. Sorry that I just found out what you are asking for. Do you mean the interface like what we do in u-boot for user to enter some commands? If so, please ignore previous answer, they are not what you are looking for.

Currently cboot boot process does not accept interrupt so cannot stop it.

I have delivered your request for stopping the cboot to internal developer. This has chance to be implemented in next release.

Hi WayneWWW:

I trace the cboot 31.1, but i found the “CONFIG_ENABLE_VERIFIED_BOOT” is not enable, did this enable check the kernel sign ? or maybe i trace the wrong direction ? if not, where is the cboot check the kernel signature ?