How to update cboot and mb1 BCT each individually on Xavier side

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
1

Hi,

I know how to update cboot and mb1 BCT each individually using flash script on host side:
For MB1 BCT:
sudo ./flash.sh -k MB1_BCT jetson-xavier mmcblk0p1
For cboot:
sudo ./flash.sh -k cpu-bootloader jetson-xavier mmcblk0p1

But I want to update cboot and mb1 BCT each individually on Xavier side. How can I do it?

Regards,
Shuo

2

Hi Shuo,

You could try to use “dd” tool to write the partition directly. Actually, it is not an official method so I will let other forum user to share their experience here.

3

Hello lunarking1028,

In the past, I have successfully updated cpu-bootloader partition on Xavier using the “dd” method. IIRC, I used to follow below steps:

  1. Build an encrypted file out of the cboot_t194.bin file:
sudo ./flash.sh --no-flash -k cpu-bootloader jetson-xavier mmcblk0p1
  1. SCP over the generated bootloader/cboot_t194_sigheader.bin.encrypt over to the Xavier.
  2. “dd” the encrypted file to the appropriate partition
dd if=/tmp/cboot_t194_sigheader.bin.encrypt of=/dev/mmcblk0p<partition_num>
  1. Reboot for the change to take effect.

AFAIK, this was working till JetPack 4.2.1. I have not tried with latest JetPack versions, but I don’t see any reason for it to not work.

4

Hi,

Thank you. I tried your steps and it works.

I have 2 more questions:

  1. Is there a way to build encrypted cboot_t194_sigheader.bin.encrypt file on Xavier side instead of using flash.sh script? And encryption of cboot is mandatory correct?

  2. How can I update MB1_BCT on Xavier side? What troubles me for MB1_BCT case is that I don’t know which mmc partition is for MB1_BCT. Base on this:
    Tegra Linux Driver

MB1_BCT is in sdmmc_boot partition instead of sdmmc_user partitions.
Which mmc partition/device name should I use for dd command to upgrade MB1_BCT?

Regards,
Shuo

5

Hello,

Good to know that it worked for you.

  1. Is there a way to build encrypted cboot_t194_sigheader.bin.encrypt file on Xavier side instead of using flash.sh script? And encryption of cboot is mandatory correct?

The binary that encrypts the binaries is an x86_64 file, so it can’t be run on Xavier. But you can build one encrypted binary and flash it on many Xaviers using the “dd” command.

For question 2, I don’t know about it, may be someone from NVIDIA can comment about it.

6

Hi NVIDIA,

Any update on how to update MB1 BCT on Xavier side? What command to use and which emmc partition to write to?

Regards,
Shuo

9