NVIDIA Jetson TX2

This article briefly describes the process of imaging a NVIDIA Jetson TX2 with Gentoo aarch64 from an amd64 host.

Prerequisites

1. Configure and install QEMU (if you wish to chroot into your image from the host machine)

root #echo 'QEMU_SOFTMMU_TARGETS="aarch64 x86_64"' >> /etc/portage/make.conf

root #echo 'QEMU_USER_TARGETS="aarch64"' >> /etc/portage/make.conf

root #echo app-emulation/qemu static-user >> /etc/portage/package.use/qemu

root #echo ':aarch64:M::\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00:\xff\xff\xff\xff\xff\xff\xff\xfc\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/bin/qemu-aarch64:' > /proc/sys/fs/binfmt_misc/register

root #echo ':aarch64:M::\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00:\xff\xff\xff\xff\xff\xff\xff\xfc\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/bin/qemu-aarch64:' > /etc/binfmt.d/qemu-aarch64-static.conf

root #systemctl restart systemd-binfmt

root #emerge --ask app-emulation/qemu

root #gpasswd -a larry kvm

root #quickpkg app-emulation/qemu

2. Setup an appropriate crossdev toolchain:

root #emerge --ask sys-devel/crossdev

root #mkdir -p /var/db/repos/crossdev/{profiles,metadata}

root #echo 'crossdev' > /var/db/repos/crossdev/profiles/repo_name

root #echo 'masters = gentoo' > /var/db/repos/crossdev/metadata/layout.conf

root #echo 'thin-manifests = true >> /var/db/repos/crossdev/metadata/layout.conf

root #chown -R portage:portage /var/db/repos/crossdev

FILE /etc/portage/repos.conf/crossdev.conf

[crossdev]
location = /var/db/repos/crossdev
priority = 10
masters = gentoo
auto-sync = no

root #crossdev --stable -t aarch64-linux-gnueabi

Creating an Image

1. Create a development space for your device and extract the L4T driver package from NVIDIA.

user $mkdir -p ~/development/jetson_tx2

user $cd ~/development/jetson_tx2

user $wget https://developer.nvidia.com/embedded/l4t/r32_release_v7.2/t186/jetson_linux_r32.7.2_aarch64.tbz2

user $tar xvfj jetson_linux_r32.7.2_aarch64.tbz2

user $cd Linux_for_tegra

2. Download and extract the latest arm64 stage3 tarball and portage snapshot.

user $wget https://gentoo.osuosl.org/releases/arm64/autobuilds/current-stage3-arm64-systemd/stage3-arm64-systemd-*.tar.xz

user $wget http://distfiles.gentoo.org/snapshots/portage-latest.tar.xz

user $cd rootfs

root #cd var/db/repos

root #mv portage gentoo

3. Apply the supplied Tegra kernel and modules.

root #cd ../../../

root #./apply_binaries.sh

4. Set the root password

root #cd rootfs

root #ROOTPASS=$(openssl passwd -6 -salt xyz «your_password_here»)

root #sed -i -e "s,^root:[^:]\+:,root:${ROOTPASS}:," etc/shadow

5. Create a non-root user

root #USERNAME=larry

root #USERPASS=$(openssl passwd -6 -salt xyz «your_password_here»)

root #mkdir -p home/${USERNAME} && cp -R etc/skel/* home/${USERNAME}/

root #chown -R ${USERNAME}:${USERNAME} home/${USERNAME}

root #chmod -R go=u,go-w home/${USERNAME} && chmod go= home/${USERNAME}

root #echo "${USERNAME}:x:1000:1000::/home/${USERNAME}:/bin/bash" >> /etc/passwd

root #echo "${USERNAME}:x:1000:" >> /etc/group

root #for group in wheel audio video users;

root # do sed -i "/^${group}:/ s/$/ ${USERNAME}/" /etc/group; done

6. Customise your system image! Emerge QEMU into the target and chroot.

root #ROOT=$PWD/ emerge --usepkgonly --oneshot --nodeps qemu

root #mount --bind /proc proc

root #mount --bind /sys sys

root #mount --bind /dev dev

root #mount --bind /dev/pts dev/pts

root #chroot . /bin/bash --login

Flashing the Image

1. Connect your device to power and via the USB recovery port to your computer.

2. Power on the board, hold the recovery button then press the reset button.

3. Enter the following command to flash your image and kernel to the device:

root #flash.sh -C console=ttyS1,115200 -C console=tty0 jetson-tx2 «root_device»

Where root_device is:

• sda1 for SATA or USB devices
• mmcblk1p1 for an attached SD card
• mmcblk0p1 for the internal eMMC