Compiling Tegra X1 source code

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Introduction

In this wiki page you are going to find the instructions to download the source code to rebuild the tegra X1 images using jetpack, several parts of this wiki were based in the document called Start_L4T_Docs.html given by Nvidia in L4T. This page should be considered a work in progress. These steps were run on Jetson TX1.
Please refer 'Getting the documentation' section in the porting NVIDIA TX1 to a New Platform for accessing Start_L4T_Docs.html file

Platform

Baseboard: P2371
Jetson module: P2180
Soc: tegra210 or tegra21x

RidgeRun SDK for tegra X1

RidgeRun offers an SDK for tegra X1 that is fully integrated with Jetpack and allows you to easily rebuild the kernel and bootloader. It can be used on the Jetson board as well as in the carrier boards from Auvidea. You can find more information about the evaluation version in the following links:

The SDK automates the steps described below and provides the infrastructure to develop your project.

Downloading the code

File called Start_L4T_Docs.html inside of Jetpack contains a good description of the packages that it contains. Let's call $DEVDIR the path where you installed your development directory or Jetpack.

1) In order to download the source code you can run the script called source_sync.sh

$DEVDIR/64_TX1/Linux_for_Tegra_64_tx1$ ./source_sync.sh

This will download the bootloader and kernel.

2) It downloads all the kernel tree but you need to specify the tag, looking into the script it seems that the tags should be specified with k and u parameters

Use: source_sync.sh [options]
Available general options are,
     -h     :     help
     -e     : exit on sync error
     -d DIR : root of source is DIR

By default, all sources are downloaded.
Only specified sources are downloaded, if one or more of the following options are mentioned.

     -k [TAG]: Download kernel source and optionally sync to TAG
     -u [TAG]: Download u-boot source and optionally sync to TAG

Repositories

k:kernel:nv-tegra.nvidia.com/linux-3.10.git:
u:u-boot:nv-tegra.nvidia.com/3rdparty/u-boot.git:

you can see the repositories on the web looking for:

http://nv-tegra.nvidia.com/gitweb/?o=age

http://nv-tegra.nvidia.com/gitweb/?p=linux-3.10.git;a=summary
http://nv-tegra.nvidia.com/gitweb/?p=3rdparty/u-boot.git;a=summary

3) It will download the git repositories for kernel and uboot but you need to specify the branch or the tag

Branch:

cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/sources/kernel_source
git branch -a
git checkout l4t/l4t-r24.2

cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/sources/u-boot_source
git branch -a
git checkout l4t/l4t-r24.2

Or if you want to download a tag then the command should look like:

./source_sync.sh -k tegra-l4t-r24.2 -u tegra-l4t-r24.2

Toolchain

Linaro or code sourcery toolchain's can be used, however, it is recommended to use the Linaro toolchain because it is newer and produces more optimized assembler code

1. Download the Linaro toolchain. You need to install two toolchains, one which is the 64bits toolchain for ARM, and the 32bits toolchain for ARM as well. In this case version 5.3-2016.02 will be used:

2. Install the toolchain

sudo mkdir /opt/linaro
sudo chmod -R 775 /opt/linaro
sudo chown -R $USER /opt/linaro
cp gcc-linaro-5.3-2016.02-x86_64_aarch64-linux-gnu.tar.xz /opt/linaro
cp gcc-linaro-5.3-2016.02-x86_64_arm-linux-gnueabihf.tar.xz /opt/linaro
cd /opt/linaro/
tar -xf gcc-linaro-5.3-2016.02-x86_64_aarch64-linux-gnu.tar.xz
tar -xf gcc-linaro-5.3-2016.02-x86_64_arm-linux-gnueabihf.tar.xz

Kernel

In order to compile the kernel please follow these steps

Build Kernel

1) Specify the path to the toolchain:

mkdir -p $DEVDIR/images/modules 
mkdir -p $DEVDIR/images/packages 
export CROSS_COMPILE=/opt/linaro/gcc-linaro-5.3-2016.02-x86_64_aarch64-linux-gnu/bin/aarch64-linux-gnu-
export CROSS32CC=/opt/linaro/gcc-linaro-5.3-2016.02-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf-gcc
export KERNEL_MODULES_OUT=$DEVDIR/images/modules
export ARCH=arm64

2) Clean your kernel and configuration

cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/sources/kernel_source/
make mrproper

3) Apply following change to avoid error: r7 cannot be used in asm here

Index: kernel_source/arch/arm64/kernel/vdso32/Makefile
===================================================================
--- kernel_source.orig/arch/arm64/kernel/vdso32/Makefile        2016-04-08 21:28:52.651992663 -0600
+++ kernel_source/arch/arm64/kernel/vdso32/Makefile     2016-04-11 12:20:03.377388110 -0600
@@ -11,7 +11,7 @@
 
 GCOV_PROFILE := n
 
-ccflags-y := -shared -fPIC -fno-common -fno-builtin -march=armv7-a
+ccflags-y := -shared -fPIC -fomit-frame-pointer -fno-common -fno-builtin -march=armv7-a
 ccflags-y += -nostdlib -Wl,-soname=linux-vdso32.so.1 \
                $(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
 asflags-y := -D__VDSO32__ -s

4) Apply following change to avoid error: logical not is only applied to the left hand side of comparison

Index: kernel_source/drivers/platform/tegra/tegra21_clocks.c
===================================================================
--- kernel_source.orig/drivers/platform/tegra/tegra21_clocks.c  2016-04-08 21:28:58.755992489 -0600
+++ kernel_source/drivers/platform/tegra/tegra21_clocks.c       2016-04-11 12:49:59.561337028 -0600
@@ -1062,7 +1062,7 @@
  */
 static void tegra21_cpu_clk_init(struct clk *c)
 {
-       c->state = (!is_lp_cluster() == (c->u.cpu.mode == MODE_G)) ? ON : OFF;
+       c->state = ((!is_lp_cluster()) == (c->u.cpu.mode == MODE_G)) ? ON : OFF;
 }
 
 static int tegra21_cpu_clk_enable(struct clk *c)

5) Configure your kernel

make tegra21_defconfig
make menuconfig

6) Compile kernel, device tree and modules

make zImage
make dtbs
make modules
make modules_install INSTALL_MOD_PATH=$KERNEL_MODULES_OUT

7) Save your binaries in the images directory

cp arch/arm64/boot/Image arch/arm64/boot/zImage $DEVDIR/images/

8) Create kernel_supplements.tbz2 with kernel modules, this package is needed by Jetpack

cd $DEVDIR/images/modules/lib/modules/
ls .

define a variable with the name of the modules directory

export KERNEL_MODULES_NAME=3.10.96+

fix the symbolic links on the kernel modules directory

cd $DEVDIR/images/modules/lib/modules/$KERNEL_MODULES_NAME
rm build source

create tarball

cd $DEVDIR/images/modules/
tar -cjf kernel_supplements.tbz2 *
mv kernel_supplements.tbz2 $DEVDIR/images/packages

9) Besides creating the modules and the kernel image you need to create again your kernel_headers.tbz2 file (needed by Jetpack). By default when you patch the kernel code and you don't check your changes in the kernel will add a -dirty suffix to the release version (check ls $DEVDIR/images/modules/lib/modules/ for example). For this specific reason you need to generate your headers tarball again changing it the release version.

cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/kernel
tar -xf kernel_headers.tbz2
tar -cjf kernel_headers_custom.tbz2 linux-headers-$KERNEL_MODULES_NAME
mv kernel_headers_custom.tbz2 $DEVDIR/images/packages
rm -rf linux-headers-$KERNEL_MODULES_NAME 

10) Create the dtb directory

mkdir -p $DEVDIR/images/dtb
cp $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/sources/kernel_source/arch/arm64/boot/dts/*.dtb $DEVDIR/images/dtb/

11) Copy the Device Tree Compiler (DTC)

cp $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/sources/kernel_source/scripts/dtc/dtc $DEVDIR/images/dtc

12) Create a backup of the images and packages included in Jetpack

mkdir -p $DEVDIR/images/packages-backup
cp -rf $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/kernel/* $DEVDIR/images/packages-backup

13) Finally overwrite the default images with your own images to install and boot them using jetpack

cd $DEVDIR/images
rm -rf $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/kernel/dtb
cp -rf Image zImage packages/kernel_supplements.tbz2 dtb/ dtc $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/kernel/
cp -rf packages/kernel_headers_custom.tbz2 $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/kernel/kernel_headers.tbz2

14) Run the applybinaries script to generate the image to flash

cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/
sudo ./apply_binaries.sh 

Output:

Using rootfs directory of: /home/dsoto/devdirs/tegra/Jetpack/TX1/Linux_for_Tegra_tx1/rootfs
Extracting the NVIDIA user space components to /home/dsoto/devdirs/tegra/Jetpack/TX1/Linux_for_Tegra_tx1/rootfs
Extracting the BSP test tools to /home/dsoto/devdirs/tegra/Jetpack/TX1/Linux_for_Tegra_tx1/rootfs
Extracting the NVIDIA gst test applications to /home/dsoto/devdirs/tegra/Jetpack/TX1/Linux_for_Tegra_tx1/rootfs
Extracting the configuration files for the supplied root filesystem to /home/dsoto/devdirs/tegra/Jetpack/TX1/Linux_for_Tegra_tx1/rootfs
Creating a symbolic link nvgstplayer pointing to nvgstplayer-0.10
Creating a symbolic link nvgstcapture pointing to nvgstcapture-0.10
Adding symlink libcuda.so --> libcuda.so.1.1 in target rootfs
Adding symlink libGL.so --> libGL.so.1 in target rootfs
Adding symlink libcuda.so --> tegra/libcuda.so in target rootfs
Adding symlink libEGL.so --> libEGL.so.1 in target rootfs
Extracting the firmwares and kernel modules to /home/dsoto/devdirs/tegra/Jetpack/TX1/Linux_for_Tegra_tx1/rootfs
Extracting the kernel headers to /usr/src in target rootfs
Installing zImage into /boot in target rootfs
Installing Image into /boot in target rootfs
Installing the board *.dtb files into /boot in target rootfs
Success!

As an important note, kernel will be located not in a partition but in /boot on the filesystem this make easier a kernel update.

Flash your image with Jetpack

You can flash your image with Jetpack now instead of using the scripts directly, however this takes time (around 10min) because we will need jetpack generating the system.img again

1. Backup your system.img

cd $DEVDIR/64_TX1/Linux_for_Tegra_tx1/bootloader/
mv system.img.raw system.img $DEVDIR/images/packages-backup/

2. Just run Jetpack as the first time that you install it:

cd $DEVDIR
./JetPack-L4T-2.1-linux-x64.run

See the Jetpack output while flashing

It will notice that everything is already build and will install your new images. If you have problems detecting the IP address wait like 2 minutes and it will give you the option to enter it manually. Username and password: ubuntu. You can see the ipaddress connecting a keyboard, mouse and monitor to the board at this point since ubuntu would be already booted.

DTB

Looking into the file $DEVDIR/TX1/Linux_for_Tegra_tx1/jetson-tx1.conf the dtb used by jetson x1 is: tegra210-jetson-tx1-p2597-2180-a01-devkit.dtb

ODMDATA=0x84000;
NET_BSF=;
EMMC_BSF=;
EMMC_BCT=P2180_A00_LP4_DSC_204Mhz.cfg;
EMMC_CFG=gnu_linux_tegraboot_emmc_full.xml;
BOOTPARTSIZE=8388608;
EMMCSIZE=31276924928;
ITS_FILE=;
SYSBOOTFILE=p2371-2180-devkit/extlinux.conf;
DTB_FILE=tegra210-jetson-tx1-p2597-2180-a01-devkit.dtb
DFLT_KERNEL=Image;
ROOTFSSIZE=14GiB;
CMDLINE_ADD="fbcon=map:0";
UBOOT_TEXT_BASE=0x8010e000;
UIMAGE_LABEL="Linux-tegra21";
target_board="t210ref";
ROOT_DEV="mmcblk0p1 ------------ internal eMMC.
        sda1 ----------------- external USB devices. (USB memory stick, HDD)
        eth0 ----------------- nfsroot via RJ45 Ethernet port.
        eth1 ----------------- nfsroot via USB Ethernet interface.";
TEGRABOOT="bootloader/${target_board}/nvtboot.bin";
SOSFILE="bootloader/nvtboot_recovery.bin";
WB0BOOT="bootloader/${target_board}/warmboot.bin";
FLASHAPP="bootloader/tegraflash.py";
FLASHER="bootloader/${target_board}/cboot.bin";
BOOTLOADER="bootloader/${target_board}/p2371-2180/u-boot-dtb.bin";
UBOOT_WITH_TBOOT=yes;
BCFFILE="bootloader/${target_board}/cfg/board_config_p2597-devkit.xml";
INITRD="bootloader/l4t_initrd.img";
TBCFILE="bootloader/nvtboot_cpu.bin";
BPFFILE="bootloader/bpmp.bin";
TOSFILE="bootloader/tos.img";
EKSFILE="bootloader/eks.img";
FBFILE="bootloader/reserved_fb.xml";

Bootloader

The bootloader is a combination of NVIDIA T-Boot (nvtboot) and U-Boot. You can read about the BOOT FLOW in the nvtboot wiki page.

According to the devtalk forum there are two ways to boot the board: fast boot and uboot

  • Fastboot is simpler, and offers no options during boot. It strictly looks for a kernel in the GPT partition from the install's "-k 6" option. This would probably be the way to go for a non-interactive embedded appliance (if not bare metal booting).
  • U-boot offers more options, and looks for a zImage in the /boot partition. Boot configuration can also be edited here, for example I threw in a couple of zImage variants (like debugging version and network options added), and edited extlinux.conf...and magically I can boot to any of those kernels at the serial console boot prompt (provided my eye is fast). No flash was required for any kernel beyond the first kernel.

Inside of the bootloader directory you will find several binaries or components, to get a description of these please read the nvtboot wiki page.

Build DTC

U-boot requires the Device Tree Compiler (dtc) which is used to compile device tree files contained in the U-Boot source tree. One version is included inside of the kernel. However, that binary is too old according to u-boot when trying to use that one

*** Your dtc is too old, please upgrade to dtc 1.4 or newer
$DEVDIR/images/dtc -v
Version: DTC 1.2.0-g37c0b6a0

In order to build it please run:

cd $DEVDIR/TX1/Linux_for_Tegra_tx1/sources
git clone git://git.kernel.org/pub/scm/utils/dtc/dtc.git
cd dtc
make
cp dtc $DEVDIR/images/

Build u-boot

1. Backup original uboot files. You see which platform you are using checking the file in $DEVDIR/TX1/Linux_for_Tegra_tx1/jetson-tx1.conf, it says:

SYSBOOTFILE=p2371-2180-devkit/extlinux.conf;

copy the files to the packages-backup directory

mkdir $DEVDIR/images/packages-backup/bootloader/
cp -rf $DEVDIR/TX1/Linux_for_Tegra_tx1/bootloader/t210ref/p2371-2180-devkit $DEVDIR/images/packages-backup/bootloader/
cd $DEVDIR/TX1/Linux_for_Tegra_tx1/bootloader/
cp nvtboot.bin nvtboot_cpu.bin u-boot-dtb.bin bpmp.bin warmboot.bin tos.img tegra210-jetson-tx1-p2597-2180-a01-devkit.dtb $DEVDIR/images/packages-backup/bootloader/
cp $DEVDIR/TX1/Linux_for_Tegra_tx1/bootloader/t210ref/p2371-2180 $DEVDIR/images/packages-backup/bootloader/

Check that all these components are flashed in one partition according to Jetpack output when flashing Tegra X1. The description of each of these components in on the t210-nvtboot-flow and tegra-boot-flow pages.

2. Go to uboot and set environment variables. You need to export the images directory path in order to allow u-boot find the DTC

cd $DEVDIR/TX1/Linux_for_Tegra_tx1/sources/u-boot_source/
PATH=$DEVDIR/images:$PATH
export CROSS_COMPILE=/opt/linaro/gcc-linaro-5.3-2016.02-x86_64_aarch64-linux-gnu/bin/aarch64-linux-gnu-
export ARCH=arm64

3. Clean and compile

make distclean
make p2371-2180_defconfig
make

4. Save your new binaries

mkdir $DEVDIR/images/bootloader
cp $DEVDIR/TX1/Linux_for_Tegra_tx1/sources/u-boot_source/u-boot{,.bin,.dtb,-dtb.bin} $DEVDIR/images/bootloader

Note: L4T U-Boot does not use the kernel partition. The kernel is installed into the filesystem alongside the boot configuration file in /boot. Aside from this difference, U-Boot has the same internal eMMC partition layout as that used by cboot.

5. Now, copy your u-boot binaries to the directory used by Jetpack to look for them. As you can see in the DTB it will look for them in

target_board="t210ref";
BOOTLOADER="bootloader/${target_board}/p2371-2180/u-boot-dtb.bin";

To copy the files run

cp  $DEVDIR/images/bootloader/u-boot{,.bin,.dtb,-dtb.bin} $DEVDIR/TX1/Linux_for_Tegra_tx1/bootloader/t210ref/p2371-2180/

6. Now run jetpack or follow the steps below to use flash.sh and let it install the new binaries as we did with the kernel. You can check the serial console output to see that u-boot has a newer date

U-Boot 2015.07-rc2 (Apr 28 2016 - 19:24:09 -0600)

If you are attached to the serial port while flashing you should see the serial port output log while flashing

Boot sequence

According to the U-boot guide provided by Nvidia uboot scans booteable devices as follows:

  • External SD Card
  • Internal eMMC
  • USB Device
  • NFS Device

It looks for an extlinux.conf configuration file in the following directory of the bootable device:

<rootfs>/boot/extlinux

Upon finding the extlinux.conf file, U-Boot does the following.

  • Uses the sysboot command to read out boot configuration from extlinux.conf,
  • Loads kernel Image file and device tree file (/boot), and then
  • Boots the kernel.

extlinux.conf is a standard text-format sysboot configuration file that contains all boot information, it is installed in /boot according to the boot method.

Boot log and uboot environment

Following boot log was obtained when connected to the serial console using the default uboot environment.

The environment is defined in extlinux.conf, however, the environment variables can be set in the uboot code directly or directly when the board is booting using the typical uboot commands like: print, saveenv, printenv, etc

Filesystem

Jetpack comes with a sample filesystem with X and ubuntu and Canonical keeps updating the packages available, you can also use your own filesystem. In both cases you have to install on it the Nvidia binaries, the instructions to do that are in the file Start_L4T_Docs.html, in the Getting started section. It mentions:

Extract the sample file system to the rootfs directory with this command:

$ sudo tar jxpf ../../Tegra-Linux-Sample-Root-Filesystem_<release_type>.tbz2

Run the apply_binaries.sh script to copy the NVIDIA user space libraries into the target file system:

$ cd ..
$ sudo ./apply_binaries.sh

If you are using a different rootfs, or if you have already configured your rootfs, apply the NVIDIA user space libraries by setting the LDK_ROOTFS_DIR environment variable to point to your rootfs. Then run the script, as shown above, to copy the binaries into your target file system.

If the apply_binaries.sh script installs the binaries correctly, the last message output from the script is “Success!”.

You can create your own ubuntu filesystem using .deb packages as sources following this instructions. The sample filesystem provided is a 32 bits filesystem, however, the kernel is a 64bits kernel. According to devtalk nvidia will be releasing a 64bits filesystem.

The remaining steps on this guide assumes that you are using the default filesytem or that you already have one built, specially for the flashing section, where flashing assumes that the filesystem already exists.

To receive notifications of new packages

1. Locate and edit the following file:

/etc/apt/sources.list

2. Add the following line:

deb http://ports.ubuntu.com/ubuntu-ports <distribution>-updates main universe

Where <distribution> is the name of the Ubuntu distribution your rootfs is based on. For example, for a rootfs based on the Trusty Tahr distribution of Ubuntu, add the line:

deb http://ports.ubuntu.com/ubuntu-ports trusty-updates main universe

Prerequisite

You have attached an Ethernet cable to the device through either the Ethernet port (if available) or through the USB Ethernet adapter. To install more packages

  • Boot the target device.
  • Verify your Ethernet connection.
  • Update the package list by executing:
$ sudo apt-get update

Note: Ensure that you run sudo apt-get update and not apt-get upgrade, which upgrades already installed packages. Do not confuse the two commands.

  • Install packages using apt-get. For example, to install wget execute this command:
$ sudo apt-get install wget

Flashing the board

Nvidia provides several scripts to help to generate the images and to flash the resulting images. Including if you are going to install uboot or fastboot. First the board needs to be in recovery mode and then the main script to flash it is $DEVDIR/Linux_for_Tegra_tx1/flash.sh. What this script will do is to install or flash the image in the desired destination. It is important that the script is controlled by variables defined in the DTB file.

# Examples:
# ./flash.sh <target_board> mmcblk0p1			- boot <target_board> from eMMC
# ./flash.sh <target_board> mmcblk1p1			- boot <target_board> from SDCARD
# ./flash.sh <target_board> sda1			- boot <target_board> from USB device
# ./flash.sh -N <IPaddr>:/nfsroot <target_board> eth0	- boot <target_board> from NFS
# ./flash.sh -k LNX <target_board> mmcblk1p1		- update <target_board> kernel
# ./flash.sh -k EBT <target_board> mmcblk1p1		- update <target_board> bootloader
#
# Optional Environment Variables:
# BCTFILE ---------------- Boot control table configuration file to be used.
# BOARDID ---------------- Pass boardid to override EEPROM value
# BOOTLOADER ------------- Bootloader binary to be flashed
# BOOTPARTLIMIT ---------- GPT data limit. (== Max BCT size + PPT size)
# BOOTPARTSIZE ----------- Total eMMC HW boot partition size.
# CFGFILE ---------------- Partition table configuration file to be used.
# CMDLINE ---------------- Target cmdline. See help for more information.
# DEVSECTSIZE ------------ Device Sector size. (default = 512Byte).
# DTBFILE ---------------- Device Tree file to be used.
# EMMCSIZE --------------- Size of target device eMMC (boot0+boot1+user).
# FLASHAPP --------------- Flash application running in host machine.
# FLASHER ---------------- Flash server running in target machine.
# IGNOREFASTBOOTCMDLINE -- Block fastboot from filling unspecified kernel
#                          cmdline parameters with its defaults.
# INITRD ----------------- Initrd image file to be flashed.
# ITSFILE ---------------- Multi image u-boot package template file.
# KERNEL_IMAGE ----------- Linux kernel zImage file to be flashed.
# MTS -------------------- MTS file name such as mts_si.
# MTSPREBOOT ------------- MTS preboot file name such as mts_preboot_si.
# NFSARGS ---------------- Static Network assignments.
#			   <C-ipa>:<S-ipa>:<G-ipa>:<netmask>
# NFSROOT ---------------- NFSROOT i.e. <my IP addr>:/exported/rootfs_dir.
# ODMDATA ---------------- Odmdata to be used.
# ROOTFSSIZE ------------- Linux RootFS size (internal emmc/nand only).
# ROOTFS_DIR ------------- Linux RootFS directory name.
# TEGRABOOT -------------- lowerlayer bootloader such as nvtboot.bin.
# UBOOTSCRIPT ------------ U-boot HUSH boot script file.
# UBOOT_TEXT_BASE -------- U-boot Image Load Address.
# UIMAGE_LABEL ----------- Kernel version for U-boot image header.
# UIMAGE_NAME ------------ uImage file name.
# WB0BOOT ---------------- Warmboot code such as nvtbootwb0.bin

Recovery mode

To put the board into force USB Recovery Mode:

1. Power down the device. If connected, remove the AC adapter from the device. The device must be
powered OFF, and not in a suspend or sleep state.
2. Connect the Micro-B plug on the USB cable to the Recovery (USB Micro-B) Port on the device and
the other end to an available USB port on the host PC.
3. Connect the power adapter to the device.
4. Press POWER button
5. Press and hold the RECOVERY FORCE (REC) button.
6. While pressing the RECOVERY FORCE button, press and release the RESET button.
7. Wait 2 seconds and release the RECOVERY FORCE button

All remaining examples assume that the board is in recovery mode

Flash filesystem

Emmc

To flash the filesystem in the emmc you need to run:

cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/
sudo ./flash.sh jetson-tx1 mmcblk0p1

USB

Important: Only for USB tegra needs a firmware that is loaded from the filesystem so the USB port is not enabled on uboot and then it causes problems to mount the fs from there, you can read about it here.

To flash the filesystem to USB you need to put the filesystem on the USB first

1) Insert your USB flash/drive in your PC and check where it was mounted

mount
/dev/sdb1 on /media/dsoto/EF02-5626 type vfat (rw,nosuid,nodev,uid=1000,gid=1000,shortname=mixed,dmask=0077,utf8=1,showexec,flush,uhelper=udisks2)

2) Format the USB drive in your PCB

umount /dev/sdb1
sudo mkfs.ext4 /dev/sdb1

3) Copy the filesystem to the USB drive. It takes a while, its size is normally 2.4GB

mkdir $DEVDIR/images/fs
sudo mount /dev/sdb1 $DEVDIR/images/fs 
cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/rootfs/
sudo cp -a * $DEVDIR/images/fs  && sync

4) Unmount the USB drive and remove it

sudo umount $DEVDIR/images/fs

5) Finally connect the USB drive to the Jetson board put the Jetson on recovery mode, flash the board to look for the filesystem on the USB port:

cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/
sudo ./flash.sh jetson-tx1 sda1 #it can be other mount point

SD card

Similar to USB but you need to replace the extlinux.conf so before copying the filesystem into the SD card run:

sudo cp $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/bootloader/t210ref/p2371-2180-devkit/extlinux.conf.sdcard $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/rootfs/boot/extlinux/extlinux.conf

then flash it

cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/
sudo ./flash.sh jetson-tx1 mmcblk1p1 

NFS

1) First you need to set up your NFS server using these instructions.

2) Open file in $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/rootfs/etc/network/interfaces and add

auto eth0
iface eth0 inet manual

3) Then flash the board to generate and install the initrd image to use nfs, you need to do this everytime that you recompile the kernel

cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/
MY_IPADDRESS=192.169.0.3
sudo ./flash.sh -N $MY_IPADDRESS:$DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/rootfs jetson-tx1 eth0

Flash kernel

To flash your kernel you just need to copy it to /boot in your filesystem. The old method to flash it in the LNX partition (./flash.sh -k LNX <target_board> mmcblk1p1) is NOT longer used

sudo cp $DEVDIR/images/zImage $DEVDIR/images/Image $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/rootfs/boot/

if you are not booting from NFS then you need to reflash your filesysm in order to update the kernel. However, likely you did some changes in the kernel modules so it is recommended to run the apply_binaries.sh script instead of only copying the kernel images.

cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/
sudo ./apply_binaries.sh 

then flash your filesystem again.

Flash bootloader

Update the content of the EBT partition where uboot is located

cd $DEVDIR/64_TX1/Linux_for_Tegra_64_tx1/
sudo ./flash.sh -k EBT jetson-tx1 mmcblk1p1

Serial Console

J21 contains the Serial Console signals as can be seen in the pin out header. Basically:

J21 Pin 8 (UART 1 TXD) -> Cable RXD
J21 Pin 10 (UART 1 RXD) -> Cable TXD
TX1 J21 Pin 9 (GND) -> Cable GND

There is a nice video with details.

References

https://devtalk.nvidia.com/default/topic/929186/jetson-tx1/jetson-tx1-kernel-compilation/
https://devtalk.nvidia.com/default/topic/762653/?comment=4654303
https://devtalk.nvidia.com/default/topic/901677/building-tx1-kernel-from-source/?offset=17
https://devtalk.nvidia.com/default/topic/760180/newbie-building-l4t-from-source-which-branch-tag-/
https://wiki.ubuntu.com/ARM/RootfsFromScratch
https://devtalk.nvidia.com/default/topic/929186/jetson-tx1/jetson-tx1-kernel-compilation/post/4854603/#4854603
https://tls.mbed.org/kb/development/arm-thumb-error-r7-cannot-be-used-in-asm-here
https://devtalk.nvidia.com/default/topic/914941/jetson-tx1/custom-kernel-compilations/post/4799773/#4799773
https://devtalk.nvidia.com/default/topic/914941/jetson-tx1/custom-kernel-compilations/2
https://devtalk.nvidia.com/default/topic/897280/jetson-tx1/jetson-tx1-with-l4t-23-1-doesn-t-support-native-aarch64-binaries-/post/4732697/#4732697
http://elinux.org/Jetson_TX1
https://devtalk.nvidia.com/default/topic/901677/jetson-tx1/building-tx1-kernel-from-source/post/4749509/#4749509
https://devtalk.nvidia.com/default/topic/905345/jetson-tx1/built-tx1-u-boot-from-source/
http://http.download.nvidia.com/tegra-public-appnotes/tegra-boot-flow.html
https://devtalk.nvidia.com/default/topic/820035/?comment=4494578
http://http.download.nvidia.com/tegra-public-appnotes/index.html
https://devtalk.nvidia.com/default/topic/781056/jetson-tk1-boot-from-nfs-system-hangs-up-during-services-boot/?offset=3
https://devtalk.nvidia.com/default/topic/744908/jetson-tk1/jetson-tk1-boot-over-nfs/

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