Chrome OS devices

This article was created to provide information on how to get Arch installed on the series of Chrome OS devices built by Acer, HP, Samsung, Toshiba, and Google. Currently this page is being overhauled, and more model specific pages are being built with some of the information listed below.

Note: This article describes how to install Arch Linux by activating developer mode. For instructions on how to install Arch Linux in a ChromeOS container without having to enable developer mode see Crostini

Related articles

Warning: This article relies on third-party scripts and modifications, and may irreparably damage your hardware or data.

Introduction

Legacy Boot Mode

All recent Intel-based Chrome OS devices (starting with the 2013 Chromebook Pixel) feature a Legacy Boot Mode, designed to allow the user to boot Linux. Legacy Boot Mode has a dedicated firmware region, RW_LEGACY, which is designed to be user-writeable (hence the 'RW' notation) and is completely separate from the ChromeOS portion of the firmware (ie, it is safe to update and cannot brick the device). It is enabled by the SeaBIOS payload of coreboot, the open-source firmware used for all Chrome OS devices (with the exception of the first generation of Chromebooks and a few early ARM models). SeaBIOS behaves like a traditional BIOS that boots into the MBR of the disk, and from there into standard bootloaders like Syslinux and GRUB.

Models with a Core-i based SoC (Haswell, Broadwell, Skylake, KabyLake) mostly ship with a functional Legacy Boot Mode payload; updating to a 3rd party build can provide bug fixes and additional features. Models with an Atom-based SoC (Baytrail, Braswell, Apollolake) have Legacy Boot Mode capability, but do not ship with a RW_LEGACY/SeaBIOS payload (that part of the firmware is blank). These models require a 3rd party RW_LEGACY firmware to be loaded for Legacy Boot Mode to be functional.

Models without Legacy Boot Mode/SeaBIOS

One of the following approaches can be taken in order to install Arch Linux on Chrome OS devices which did not ship with SeaBIOS as part of the installed firmware:

  • If the device supports Legacy Boot Mode, but does not ship with a functional RW_LEGACY payload (or does not ship with one at all), one can flash a SeaBIOS payload to the RW_LEGACY part of the firmware. This is 100% safe, as it writes to a user-writeable area of the firmware image which is completely separate from/does not affect ChromeOS. The easiest way to install/update the RW_LEGACY firmware on your ChromeOS device is via MrChromebox's Firmware Utility Script, which supports the widest range of devices and offers the most up-to-date SeaBIOS builds; one can also update the RW_LEGACY firmware manually with Chrome OS' flashrom (requires downloading/compiling your own build), or use John Lewis' flash_chromebook_rom.sh script (no longer supported).
  • Flash a full custom firmware which includes either a SeaBIOS or UEFI payload, and removes all the ChromeOS-specific parts.
  • Flash the part of the firmware. This method replaces the stock ChromeOS payload (depthcharge) with SeaBIOS. This is theoretically a safer approach than flashing the full firmware but there might be some limitations (e.g. no support in suspend or VMX). This is the option in John Lewis' flash_chromebook_rom.sh script and option in MrChromebox's.
  • Take the ChrUbuntu approach which uses the Chrome OS kernel and modules.
  • Build and sign your own kernel, see .

The Installation process described on this page tries to cover the method of installing Arch Linux on models without SeaBIOS by flashing a custom firmware.

Firmware write protection intro

All Chrome OS devices features firmware write protection, which restricts write access to certain regions of the flash chip. It is important to be aware of it as one might need to disable the hardware write protection as part of the installation process (to update GBB flags or flash a custom firmware).

For more details see Custom firmware for Chrome OS devices#Firmware write protection.

Prerequisites
  • You should claim your free 100GB-1TB of Google Drive space before you install Arch. This needs to happen from ChromeOS(version > 23), not linux. This will sync/backup ChromeOS, as designed
  • Visit the ArchWiki page for your Chrome OS device.
  • If there is no ArchWiki page for your device then before proceeding, gather information about the device and if you succeed in installing Arch Linux, then consider adding a new ArchWiki page for your model (you can use the Acer C720 as an example for device shipped with SeaBios or the Acer C710 as device that did not ship with it).
  • Read this guide completely and make sure you understand all the steps before making any changes.

Chrome OS devices

See Chrome OS devices/Chromebook for hardware comparison with details about SeaBIOS availability and storage expansion.

General hardware recommendations and remarks
  • MyDigitalSSD M.2 NGFF SSD drives are probably the most popular choice when upgrading the internal SSD of a Chrome OS device. There are multiple accounts of failing MyDigitalSSD SSD drives at the Acer C720 topic on the Arch forums and much more on the web. If the SSD was upgraded to a MyDigitalSSD model then it is highly recommended to backup the system and data frequently. It might be advisable to upgrade the SSD with a different brand. Notice that this might be due to a SSD firmware issue so updating the SSD firmware is highly recommended.
  • Transcend MTS400 M.2 NGFF SSD drives are failing (at least with stock Coreboot firmware) when ALPM is enabled, ATM there is no SSD firmware update that fixing this bug, so it is highly advisable to disabled ALPM if a power management daemon has been installed (which enabled it), see Resolving SATA power management related errors and how to disable ALPM in Chrome OS.

Installation
Warning: Installation on ChromeOS devices that do not ship with SeaBIOS requires flashing a custom firmware, certain types of which have the potential to brick your device.

The general installation procedure:

  • Enable developer mode.
  • ChromeOS device with functional Legacy Boot Mode/SeaBIOS:
    • Enable Legacy Boot Mode.
    • Set SeaBIOS as default (optional but highly recommended, requires disabling the write protection).
  • ChromeOS device without functional Legacy Boot Mode:
    • Flash one of the following types of custom firmware
      • Flash RW_LEGACY firmware (zero risk)
      • Flash BOOT_STUB firmware (very low risk).
      • Flash Full custom firmware (low risk).
  • Prepare the installation media.
  • Boot Arch Linux installation media and install Arch.

Enabling developer mode

Developer Mode is necessary in order to access the superuser shell inside ChromeOS, which is required for making changes to the system like allow booting through SeaBIOS.

To enable developer mode:

  • Press and hold the (where would normally be) keys, then press the button. This enters Recovery Mode.
    • Chromeboxes have a dedicated Recovery button, which should be pressed/held while powering on
  • Press (no prompt). It will ask you to confirm, then the system will revert its state and enable Developer Mode.

Accessing the superuser shell

After you have enabled the Developer Mode, you will need to access the superuser shell. How you do this depends on whether you have configured ChromeOS or not.

Accessing the superuser shell without logging into ChromeOS

If you have not configured ChromeOS, just press (F2 is the "forward" arrow on the top row, →), you will see a login prompt.

  • Use chronos as the username, it should not prompt you for a password.
  • Become superuser with sudo, use the command .

Accessing the superuser shell when logged into ChromeOS

If you have configured ChromeOS already:

  • Open a crosh window with .
  • Open a bash shell with the command.
  • Become superuser with sudo, use the command to accomplish that.

Enabling Legacy Boot Mode

If your ChromeOS device did not ship with Legacy Boot Mode support via SeaBIOS, or you prefer to install a custom firmware, then continue to #Flashing a custom firmware.

This will enable the pre-installed version of SeaBIOS through the Developer Mode screen in coreboot.

  • Inside your superuser shell enter:
# crossystem dev_boot_legacy=1
  • Reboot the machine.

You can now start SeaBIOS by pressing at the white boot splash screen.

You should now have SeaBIOS enabled on your ChromeOS device, if you choose to not set it as default then you can continue to #Installing Arch Linux.

Boot to SeaBIOS by default

To boot SeaBIOS by default, you will need to run the set_gbb_flags.sh script, which is part of ChromeOS. The script uses flashrom and gbb_utility to read the RO_GBB firmware region, modify the flags, and write it back to flash. The GBB flags can also be set using MrChromebox's Firmware Utility Script under either ChromeOS or Arch (the latter requiring booting with specific kernel parameters to relax memory access restrictions).

  • Disable the hardware write protection.
To find the location of the hardware write-protect screw/switch/jumper and how to disable it, visit the ArchWiki page for your ChromeOS device. If there is no information about your device on the ArchWiki then turn to Developer Information for ChromeOS Devices and coreboot's Chromebooks page.
More information about the firmware protection available in Chrome OS devices/Custom firmware#Firmware write protection.
# flashrom --wp-disable
  • Check that write protection is disabled.
# flashrom --wp-status
  • Run with no parameters.
# /usr/share/vboot/bin/set_gbb_flags.sh
  • This will list all of the available flags. The ones of interest to us are:
GBB_FLAG_DEV_SCREEN_SHORT_DELAY 0x00000001
GBB_FLAG_FORCE_DEV_SWITCH_ON 0x00000008
GBB_FLAG_FORCE_DEV_BOOT_LEGACY 0x00000080
GBB_FLAG_DEFAULT_DEV_BOOT_LEGACY 0x00000400
  • So, to set SeaBIOS as default, with a 1s timeout, prevent accidentally exiting Developer Mode via spacebar, and ensure Legacy Boot Mode remains enabled in the event of battery drain/disconnect, we set the flags as such:
# /usr/share/vboot/bin/set_gbb_flags.sh 0x489
  • Enable back the software write protection.
# flashrom --wp-enable

Your ChromeOS device now will boot to SeaBIOS by default, you can continue to Installing Arch Linux, if your device is booting correctly then you can optionally re-enable the hardware write protection.

Flashing a custom firmware
Note: The following steps explain how to flash a custom firmware from ChromeOS, for information on how to flash a custom firmware from Arch Linux visit the Chrome OS devices/Custom firmware page
  • Disable the hardware write protection.
You will need to disable hardware write-protect either using a switch, jumper or screw, or by disconnecting the battery. To find out how to disable it visit the ArchWiki page for your ChromeOS device. If there is no information about your device on the ArchWiki then turn to Developer Information for ChromeOS Devices and coreboot's Chromebooks page.
More information about the firmware protection available in Chrome OS devices/Custom firmware#Firmware write protection.
  • Enter the command to run either MrChromebox's or John Lewis's firmware script.
  • After the exiting the script, be sure to copy the backed up firmware to an external storage before rebooting the system (if the script does not provide that option for you).

You should now have a custom firmware installed on your device, cross your fingers and reboot.

After flashing the firmware you can continue to #Installing Arch Linux.

Preparing the installation media

Create an Arch Linux Installer USB drive.

Booting the installation media
  • Plug the USB drive to the ChromeOS device and start SeaBIOS with at the white boot splash screen (if SeaBIOS is not set as default).
  • Press Esc to get a boot menu and select the number corresponding to your USB drive.

The Arch Linux installer boot menu should appear and the installation process can proceed as normal.

After finishing installing Arch Linux continue by following the Post Installation Configuration.

Post installation configuration

Patched kernels

It is recommended to use the official package for most Chrome OS devices with the exception being newer devices which might need patched kernel support.

If your devices requires a patched kernel, it is advised to review the list of patches and decide if the patch list is getting decidedly small enough that you no longer require a patched kernel and instead you can use the official package instead.

See kernels for more information.

Video driver

See Intel graphics.

Touchpad and touchscreen

See Touchpad Synaptics, libinput, and Touchscreen.

Touchpad and touchscreen kernel modules

Since kernel 3.17 all the related patches merged into the upstream sources, meaning the package in core supports these devices.

What to do if your touchpad or touchscreen is not supported?
  • Do not worry as the developers should be able to add it by request as the Chromium OS sources includes the related changes.
  • You can also try to find the related commits by yourself and create a proper patch, some hints:
    • Dig into your Chrome OS system, look at the obvious suspects like boot log, and .
    • The Linux kernel sources for Chromium OS are at .
    • Each kernel source for the latest Chromium OS release has its own branch, name convention: , where is the Chromium OS release and KERNELVER is the kernel version.
    • Review the git log of , and drivers/input/touchscreen.

Touchpad configuration

There are few options how to set the touchpad:

Chromium OS input drivers

 
offers a port of the Chromium OS input driver: xf86-input-cmt as an alternative for the Synaptics input driver. It provides tweaked configuration files for most devices, and provides functionality that the Synaptics input driver does not such as palm rejection. Additionally, it enables functionality not enabled by default in the Chromium OS input driver such as tap-to-drag.

Please note, the input driver does not work under some circumstances where you have insufficient permissions to access This will affect you if you use startx to load a DE/WM session. If this is the case or if the driver does not load for any other cases, you should run:

# usermod -a -G input $USER

Where $USER is the current user wanting to use the input driver.

It should also be noted that some users have reported the driver does not work in GDM but works normally after log in. If you are affected by this, you should run:

# usermod -a -G input gdm

After reboot, you should be able to use the touchpad normally.

Fixing suspend

The following are instructions to fix the suspend functionality. Users of a pre-installed SeaBIOS or John Lewis' pre-built SeaBIOS you will need this fix. This procedure is not needed with Matt DeVillier's custom firmware since problematic ACPI wake devices (such as ) are firmware-disabled.

There have been a few alternatives discussed and those may work better for some.

To fix suspend, the general idea is to disable the EHCI_PCI module, which interferes with the suspend cycle. There are multiple ways to achieve this.

With kernel parameters

Add the following to your GRUB configuration:-

Then rebuild your grub config. After rebuilding your GRUB config, reboot your computer.

User reports needing to blacklist and cros_ec_typec instead of the above module to get suspend & resume working on an 11th gen Acer Chromebook CX5500 running Arch Linux via SeaBIOS.

With systemd

Sometimes the synaptics touchpad, and various other parts of the laptop are used as wakeup devices causing certain movements of the laptop during suspend to end suspend. In order to disable all wakeup devices except for the laptop lid sensor, create the following file. 

/usr/local/sbin/suspend-device-fix.sh
#!/bin/bash

awk '{if ($1 != "LID0" && $3 == "*enabled") print $1}' < /proc/acpi/wakeup | while read NAME
do echo "$NAME" > /proc/acpi/wakeup
done

exit 0

Now make the file executable

Create a systemd service to execute the script on every boot.

First start . If it properly starts, then enable it to be started on bootup.

Add the following line at the end of (if it does not exist, just create it) to prevent bad handling of EHCI USB:

Then, create the following file. Only the Ath9k binding/unbinding lines are listed below; see the alternatives linked above for additional sound suspend handling if you experience issues.

Make sure to make the script executable.

Then rebuild your grub config.

Baytrail based models

Audio on most baytrail models should work on since fix merged into 4.19.7 , to fix regression in 4.18.15, see bug report .

It is likely that you will also need to use alsamixer from to turn on "Left Speaker Mixer Left DAC" and "Right Speaker Mixer Right DAC". For more information, see .

If you use max98090, you may also need to install Advanced Linux Sound Architecture#ALSA firmware and symbolically link to /usr/lib/firmware/sof-byt-max98090.tplg.

Haswell based models

One or more of followings might help solving audio related issues, setting module index reported the most useful. It is highly possible that you will not need to make any change.

  • Create , the option will make sure the analog output is the default (and not HDMI), the option will notify the driver our board model which will make the built-in microphone usable (you can try instead or model=,alc283-dac-wcaps).
  • Use the file from .
  • If having problems with headphones (perhaps no audio playing), try (requires ) in terminal. Now, ALSA should automatically switch between channels when using headphones/speakers.
  • To fix Flash audio with PulseAudio, use the file from .

Hotkeys

The Chromebook function keys recognized as standard F1-F10 by the kernel, it is preferable to map them accordingly to their appearance. It would also be nice to get the keys which in Chrome OS mapped to Alt+: BackSpace, Right, Left, Up, Down.

xkeyboard configuration

 
2.16-1 added a  model that enables the Chrome OS style functions for the function keys.  You can, for example, set this using .  See the  definition in  for the full mappings.

Sxhkd configuration

One way to set the hotkeys would be by using the Sxhkd daemon. Besides sxhkd, this also requires amixer, , and .

See for an example configuration in .

Xbindkeys configuration

Another way to configure hotkeys would be by using Xbindkeys. Besides this requires amixer and and .

Alternate xbindkeys configuration

Volchange (originated in the Debian User Forums)) can manipulate the volume with PulseAudio instead of using amixer. Besides Volchange this requires and .

See for a matching ~/.xbindkeysrc.

Patch xkeyboard-config

Another option is to install , for more details visit .

Mapping in GNOME with gsettings set

Some of the function keys can be mapped in Gnome with the advantage of HUD notifications on changes (like volume and brightness changes) which can supplement one of the mapping methods mentioned above. This linked example maps the brightness and volume actions. Notice that is required.

Ignore using logind

Out of the box, will catch power key and lid switch events and handle them: it will shut down the Chromebook on a power key press, and a suspend on a lid close. However, this policy might be a bit harsh given that the power key is an ordinary key at the top right of the keyboard that might be pressed accidentally.

To configure logind to ignore power key presses and lid switches, add the lines to below.

Then restart logind for the changes to take effect.

Power key and lid switch events will still be logged to journald by logind. See Power management#ACPI events.

Ignore by Gnome

Install gnome-tweaks, open the Tweak Tool and under Power change the Power Button Action.

Known issues

Syslinux

Follow Syslinux installation instructions carefully. Try manual installation to see where the problem comes from. If you see Missing Operation System then it may be because you need to use correct bootloader binary. If syslinux does not work try another bootloader such as GRUB.

gollark: !roll d6
gollark: (This is from my mine)
gollark: !q give 100 fuel <@!258639553357676545>
gollark: !q take 10 bricks <@!258639553357676545>
gollark: Wait, did the names of *all* the roles get changed to annoy that person complaining about the default one?

See also
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