Samsung Chromebook

The Samsung Chromebook XE303C12 is a new line of ultraportables designed specifically for Google's Chrome OS. Powered by a Samsung Exynos 5250, it gives you two cores running at 1.7GHz each and an included Mali-T604 quad-core GPU.

  • Exynos 5250 Dual-Core @ 1.7Ghz
  • 2GB DDR3L
  • 16GB eMMC
  • 11.6" / 1366x768
  • 802.11 a/b/g/n (Dual Band)
  • VGA (dongle)
  • HDMI
  • 1x USB 3.0 / 1x USB 2.0
ARMv7 Cortex-A15
Samsung Exynos 5250 1.7GHz
Full SD
  • These instructions will create a dual-booting environment where you can switch between booting Arch Linux ARM and the stock ChromeOS. No changes are made to the internal eMMC drive, and your new Arch Linux ARM install will run completely from external storage. This is the recommended setup for those that just want to take a test drive, or don't want to give up ChromeOS.
  • You must be running the latest ChromeOS prior to installation.

Switch to developer mode

  1. Turn off the laptop.
  2. To invoke Recovery mode, you hold down the ESC and Refresh keys and poke the Power button.
  3. At the Recovery screen press Ctrl-D (there's no prompt - you have to know to do it).
  4. Confirm switching to developer mode by pressing enter, and the laptop will reboot and reset the system. This takes about 15-20 minutes.

Note: After enabling developer mode, you will need to press Ctrl-D each time you boot, or wait 30 seconds to continue booting.

Enable booting from external storage

  1. After booting into developer mode, hold Ctrl and Alt and poke the T key. This will open up the crosh shell.
  2. Type shell to get into a bash shell.
  3. Type sudo su to become root.
  4. Then type this to enable USB booting:
    crossystem dev_boot_usb=1 dev_boot_signed_only=0
  5. Reboot the system to allow the change to take effect.

Create a root USB or SD for dual booting

These instructions are written for installing to a USB drive with the sda device, assuming no other USB drives are plugged in. For an SD card, click here to magically adjust the instructions for the mmcblk1 device that an SD card will register as.
  1. Get a root shell as described in the previous section.
  2. Since ChromeOS will automatically mount any partitions it finds, unmount everything now:
    umount /dev/sda*
  3. Start fdisk to create a GPT partition table:
    fdisk /dev/sda
  4. At the fdisk prompt:
    1. Type g. This will create a new empty GPT partition table.
    2. Write the partition table and exit by typing w.
  5. Partition the micro SD card:
    cgpt create /dev/sda
    cgpt add -i 1 -t kernel -b 8192 -s 32768 -l Kernel -S 1 -T 5 -P 10 /dev/sda
  6. To create the rootfs partition, we first need to calculate how big to make the partition using information from cgpt show. Look for the number under the start column for Sec GPT table which is 15633375 in this example:
    localhost / # cgpt show /dev/sda
           start        size    part  contents
               0           1          PMBR
               1           1          Pri GPT header
            8192       32768      1   Label: "Kernel"
                                      Type: ChromeOS kernel
                                      UUID: E3DA8325-83E1-2C43-BA9D-8B29EFFA5BC4
                                      Attr: priority=10 tries=5 successful=1
    15633375 32 Sec GPT table 15633407 1 Sec GPT header
  7. Replace the xxxxx string in the following command with that number to create the root partition:
    cgpt add -i 2 -t data -b 40960 -s `expr xxxxx - 40960` -l Root /dev/sda
  8. Tell the system to refresh what it knows about the disk partitions:
    partx -a /dev/sda
  9. Format the root partition:
    mkfs.ext4 /dev/sda2
  10. Download and extract rootfs tarball:
    cd /tmp
    curl -LO
    mkdir root
    mount /dev/sda2 root
    tar -xf ArchLinuxARM-armv7-chromebook-latest.tar.gz -C root
  11. Flash the kernel to the kernel partition:
    dd if=root/boot/vmlinux.kpart of=/dev/sda1
  12. Unmount the root partition:
    umount root
  13. Reboot the computer.
  14. At the splash screen, instead of pressing Ctrl-D to go to ChromeOS, press Ctrl-U to boot to the external drive.
  15. After logging in as root (password is "root"), you can connect to a wireless network by running:
  16. Initialize the pacman keyring and populate the Arch Linux ARM package signing keys:
    pacman-key --init
    pacman-key --populate archlinuxarm

Mainline Kernel

The installation above will use the mainline kernel. If you are still using the ChromeOS 3.8 kernel (linux-peach), you can switch to mainline two different ways:

  1. Replace kernel packages
    1. Install linux-armv7 packages, replacing the linux-peach package:
      pacman -S linux-armv7 linux-armv7-chromebook
    2. Type y and hit enter when prompted to flash the kernel to the kernel partition.
    3. Reboot.
  2. Perform a new installation with the above steps.

Better touchpad responsiveness

Create the file /etc/X11/xorg.conf.d/50-touchpad.conf and add the following to it:

Section "InputClass"
        Identifier              "touchpad"
        MatchIsTouchpad         "on"
        Option                  "FingerHigh"    "5"
        Option                  "FingerLow"     "5"

Enable audio

  1. Install alsa-utils: pacman -S alsa-utils
  2. Run alsamixer as root.
  3. Select correct sound card by pressing F6 and selecting '0 Snow-I2S-MAX98095'
  4. Arrow right until you see four items starting with Left Speaker Mixer, and press M on all four channels to un-mute them.
  5. Arrow right some more until you find four more starting with Right Speaker Mixer and un-mute them as well.
  6. Arrow all the way back left to the Speaker channel and raise the volume a little. Keep it low (< 50ish), since alsa will let you get dangerously high for these speakers.

Alternatively, the following commands can be issued per channel to amixer. Requires alsa-utils as well.

amixer -c 0 set 'Right Speaker Mixer Right DAC1' unmute 
amixer -c 0 set 'Right Speaker Mixer Mono DAC3' unmute
amixer -c 0 set 'Right Speaker Mixer Mono DAC2' unmute
amixer -c 0 set 'Right Speaker Mixer Left DAC1' unmute
amixer -c 0 set 'Left Speaker Mixer Right DAC1' unmute
amixer -c 0 set 'Left Speaker Mixer Mono DAC3' unmute
amixer -c 0 set 'Left Speaker Mixer Mono DAC2' unmute
amixer -c 0 set 'Left Speaker Mixer Left DAC1' unmute

Suspend when closing the lid

Install acpid and pm-utils: pacman -S acpid pm-utils

Edit /etc/acpi/ and near the bottom you'll see the button/lid section. Add pm-suspend to the close section to look like:

    case "$3" in
            logger 'LID closed'

Enable and start acpid:

systemctl enable acpid
systemctl start acpid

Closing the lid will now trigger a suspend, and opening it will wake the system.

User permissions for backlight control

To allow all users to modify the backlight control at /sys/class/backlight/backlight/brightness, create and edit the file /etc/tmpfiles.d/brightness.conf with these contents:

f /sys/class/backlight/backlight/brightness 0666 - - - 800

On boot, systemd will now set the permissions of that control file to be world writable. Acceptable values are 0-7.

Copyright ©2009-2022 Arch Linux ARM
The registered trademark Linux® is used pursuant to a sublicense from LMI, the exclusive licensee of Linus Torvalds, owner of the mark on a world-wide basis.
The Arch Linux™ name and logo are used under permission of the Arch Linux Project Lead.