TX2 Flashing Guide

Hardware Preparation

You would need a PC with Ubuntu OS, a TX2 and its power cable, a microUSB-USB cable.

Restore image to TX2

On the Ubuntu PC:

0. Prepare flashing environment L4T Version 28.2.1, with patch from Auvidea, by downloading and de-compresssing Linux_for_Tegra_J120.zip. This whole folder contains the files and binaries for all the hidden partitions (including bootloaders, kernels and dtb files). This also contains the scripts provided by Nvidia, for flashing (e.g. flash.sh)

1. Download the backup_***.img backup image from the same folder of Linux_for_Tegra_J120.zip

   • (Optional) Double check image’s md5 checksum (by entering the codes below) to ensure data integrity. This image file contains the data for APP partition, which is the only visible partition when TX2 boots up. This APP partition contains all the root filesystem for Linux running.

Go to the downloaded location of backup_***.img, and

md5sum backup_190413.img
Wait for a while (can take a couple of minutes), result shows ( The current checksum is a890c99b1676b23265f2bc4450a72d04 backup_190413.img )

2. Go to the Linus_for_Tegra_J120 folder, in the bootloader/ folder, make a soft symbolic link in the Linux_for_Tegra/bootloader folder (ln -s “the location of your .img file” system.img):

   ln -s ../../../images/backup_190413.img system.img

   It should always be named system.img

3. Put tx2 into recovery mode,

   • You could enter the recovery mode by REC-press and hold -> RST-press and hold -> RST-release -> wait 2 sec -> REC-release on the development board for TX2.
   • if not successfull, you could still enter by interrupting the bootloader in the UART console, and by typing enterrcm

and then plug in the OTG micro-USB port (hidden on the left of the atennas) into the host PC. Different from a thumbdrive, note that it won’t pop out automatically.

Check the connection by opening a terminal, key in

lsusb should show ID 0955:7c18 NVidia Corp.

4. Go to the Linux_for_Tegra/ folder, open it in terminal,

   sudo ./flash.sh -r jetson-tx2 mmcblk0p1 Wait for approx. 20 min, and TX2 should automatically restart after successful flashing.

5. Done :)

Backup TX2 to image

1. To minimise image size, consider using zerofree utility to erase unallocated disk space to zeros, in read-only filesystem mount within TX2.
2. In the Linux_for_Tegra/ folder, perform backup of the APP partition

   sudo ./flash.sh -r -k APP -G backup.img jetson-tx2 mmcblk0p1

Regarding Sparse Image (*.img.raw)

Historically there was not always a sparse (compressed image), but due to how long it took to copy over USB2 the sparse image had support added. Prior to sparse images the flash program just used the raw image directly. The current flash program can still use an uncompressed/raw image. The order of dealing with flash images is that "bootloader/system.img" is created; this is then moved to "bootloader/system.img.raw", and then system.img.raw is used to compress into system.img. flash.sh does not care if system.img is raw or sparse, it works.

https://devtalk.nvidia.com/default/topic/1009158/jetson-tx2/cloning-or-taking-snapshot-of-tx2-board/

• To make the sparse .img out of .img.raw, use the following command \

  ./mksparse -v --fillpattern=0 system.img.raw system.img

NOTE: This Linux for Tegra folder has been patched with Auvidea firmware for J120 Board

• The original driver could be found at L4T 28.2.1(Kernel 4.4)

• The Auvidea patch could be found at May 2018 V1.6

IMPORTATNT: You have to flash the image with the correct kernel and DTB files, in addition to flash the system.img to APP partitions. This is because the kernel and device tree files are flashed to hidden partitions by the ./flash.sh script. This is why the stock L4T 28.2.1 will NOT work. The J120 patch must be applied (which is already done for you here).