Compiling Jetson Nano source code L4T 32.1
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Introduction
This wiki page contains instructions to download and build kernel source code for Jetson Nano. L4T 32.1 is used by JetPack 4.2 (You can get more information from jetpack-archive).
Compiling the kernel sources
Dependencies
The first step is to install some important dependencies, make sure you have installed this before compile the kernel sources.
sudo apt install build-essential bc bzip2 xz-utils git-core vim-common
Environment variables
These environment variables are used to compile the kernel and belong to the L4T 32.1 release.
VERSION=32-1-0 TOOLCHAIN_SRC=kernel-gcc-6-4-tool-chain TOOLCHAIN_DIR=gcc-linaro-6.4.1-2017.08-x86_64_aarch64-linux-gnu KERNEL_SRC=l4t-sources-32-1-0 KERNEL_DIR=kernel-4.9 CC_PREFIX=aarch64-linux-gnu-
Toolchain
In order to compile the kernel sources you need to install the toolchain just running the next commands:
cd ~
mkdir -p toolchain_bin_$VERSION
cd toolchain_bin_$VERSION
# Reuse existing download, if any
if ! test -e ${TOOLCHAIN_SRC}.tar.gz; then
wget -O ${TOOLCHAIN_SRC}.tar.gz https://developer.nvidia.com/embedded/dlc/${TOOLCHAIN_SRC}
tar -xf ${TOOLCHAIN_SRC}.tar.gz
fi
Downloading Kernel sources
Not stable
This is not stable because the source_sync.sh script, usually has to fetch inner repositories, but many times this doesn't happen as expected and several issues can be found. In this step you need to have installed JetPack 4.2 for nano boards.
JETPACK=~/JetPack-L4T-4.2
cd ${JETPACK}/JetPack_4.2_Linux_P3448/Linux_for_Tegra/
./source_sync.sh
##
# When prompted, use: tegra-l4t-r32.1 as the tag (change accordingly)
##
Stable
With this method, you are downloading all the source at once, and you don't have to fetch inner repositories since they are downloaded at the same time.
JETSON_NANO_SOURCES=$(pwd) wget https://developer.download.nvidia.com/embedded/L4T/r32_Release_v1.0/jetson-nano/BSP/Jetson-Nano-public_sources.tbz2 tar -xvf Jetson-Nano-public_sources.tbz2 cd public_sources/ tar -xvf kernel_src.tbz2
Compiling the Kernel sources
Once you have downloaded the kernel sources and you have installed the toolchain you will be able to start compiling the kernel sources.
JETPACK=~/JetPack-L4T-4.2
CROSS_COMPILE=${HOME}/toolchain_bin_${VERSION}/${TOOLCHAIN_DIR}/bin/$CC_PREFIX
KERNEL_OUT=${JETPACK}/JetPack_4.2_Linux_P3448/Linux_for_Tegra/sources/kernel/${KERNEL_DIR}/build
KERNEL_MODULES_OUT=${JETPACK}/JetPack_4.2_Linux_P3448/Linux_for_Tegra/rootfs
cd ${JETPACK}/JetPack_4.2_Linux_P3448/Linux_for_Tegra/sources/kernel/${KERNEL_DIR}
mkdir -p $KERNEL_OUT
# Create the .config file
make ARCH=arm64 O=$KERNEL_OUT tegra_defconfig
make ARCH=arm64 O=$KERNEL_OUT menuconfig
# Build the kernel and DTBs
make ARCH=arm64 O=$KERNEL_OUT CROSS_COMPILE=${CROSS_COMPILE} -j4
Flashing Jetson Nano completely including FS
With the next command you will be able to flash the kernel image, dtb and also file system.
# flash whole file system sudo ./flash.sh jetson-nano-qspi-sd mmcblk0p1
Flash custom DTB on the Jetson Nano
With the next command you will be able to flash only the device tree, excluding kernel image and filesystem, just make sure to put the board in recovery mode.
#flash just DTB
cd ${JETPACK}/JetPack_4.2_Linux_P3448/Linux_for_Tegra/
cp sources/kernel/kernel-4.9/build/arch/arm64/boot/dts/tegra210-p3448-0000-p3449-0000-a02.dtb kernel/dtb/
sudo ./flash.sh -r -k DTB jetson-nano-qspi-sd mmcblk0p1
Flash DTB from the Jetson device itself
The DTB file needs to be placed into a specific partition and signed as encrypted.
- Generate the encrypted DTB:
cp sources/kernel/kernel-4.9/build/arch/arm64/boot/dts/tegra210-p3448-0000-p3449-0000-a02.dtb kernel/dtb/
sudo ./create-jetson-nano-sd-card-image.sh -o sd-blob.img -s 4G -r 200
# The above command will generate the encrypted dtb on the following path:
# ${JETPACK}/JetPack_4.2_Linux_P3448/Linux_for_Tegra/bootloader/signed/tegra210-p3448-0000-p3449-0000-a02.dtb.encrypt
- Flash the encrypted DTB to the DTB partition:
# Pull the SD card out of the Nano and put into your Linux machine
sudo dd if=${JETPACK}/JetPack_4.2_Linux_P3448/Linux_for_Tegra/bootloader/signed/tegra210-p3448-0000-p3449-0000-a02.dtb.encrypt of=/dev/<DTB_PARTITION>
# This will program the DTB file into the DTB partition. Use the "ls -al /dev/disk/by-partlabel" command on your Linux host machine to check for the NANO SD card DTB partition.
# Put the SD card back in the Nano and reboot
#Also, you could transfer the tegra210-p3448-0000-p3449-0000-a02.dtb.encrypt file to the nano board and flash it from the Nano board itself.
sudo dd if=tegra210-p3448-0000-p3449-0000-a02.dtb.encrypt of=/dev/<DTB_PARTITION>
#Verify which is your JETSON NANO DTB partition
nvidia@nvidia:~$ ls -al /dev/disk/by-partlabel
total 0
drwxr-xr-x 2 root root 320 jun 21 08:16 .
drwxr-xr-x 8 root root 160 jun 21 08:16 ..
lrwxrwxrwx 1 root root 15 jun 21 08:16 APP -> ../../mmcblk0p1
lrwxrwxrwx 1 root root 16 jun 21 08:16 BMP -> ../../mmcblk0p13
lrwxrwxrwx 1 root root 15 jun 21 08:16 BPF -> ../../mmcblk0p6
lrwxrwxrwx 1 root root 15 jun 21 08:16 BPF-DTB -> ../../mmcblk0p7
lrwxrwxrwx 1 root root 16 jun 21 08:16 DTB -> ../../mmcblk0p10 # This is the DTB PARTITION WERE THE ENCRYPTED DTB FILE SHOULD BE FLASHED
lrwxrwxrwx 1 root root 15 jun 21 08:16 EBT -> ../../mmcblk0p4
lrwxrwxrwx 1 root root 16 jun 21 08:16 EKS -> ../../mmcblk0p12
lrwxrwxrwx 1 root root 15 jun 21 08:16 FX -> ../../mmcblk0p8
lrwxrwxrwx 1 root root 16 jun 21 08:16 LNX -> ../../mmcblk0p11
lrwxrwxrwx 1 root root 15 jun 21 08:16 RP1 -> ../../mmcblk0p3
lrwxrwxrwx 1 root root 16 jun 21 08:16 RP4 -> ../../mmcblk0p14
lrwxrwxrwx 1 root root 15 jun 21 08:16 TBC -> ../../mmcblk0p2
lrwxrwxrwx 1 root root 15 jun 21 08:16 TOS -> ../../mmcblk0p9
lrwxrwxrwx 1 root root 15 jun 21 08:16 WB0 -> ../../mmcblk0p5
#Reboot board
sudo reboot
Flash Custom Kernel Image
In order to replace the kernel image you need to copy the Image file to the Jetson nano to the directory /boot/ send the custom kernel image binary to the Jetson Nano:
NANO_IP=10.251.101.144 scp sources/kernel/kernel-4.9/build/arch/arm64/boot/Image nvidia@<$NANO_IP>:
Then in the Jetson Nano board replace the file as:
cd ~/ sudo cp Image /boot/ sudo mv /lib/modules/4.9.140-tegra/ /lib/modules/4.9.140 sudo reboot
Reboot the system after replacing the Image is important.
SDcard Image Clone
In order to clone a SDcard Image with all the partitions required by the Jetson Nano run the following command:
sudo dd if=/dev/mmcblk0 of=sdimage-jetson-nano.img bs=4M
To flash the SDcard with the previous content run the following command:
sudo dd if=sdimage-jetson-nano.img of=/dev/mmcblk0 bs=1M
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