Acer Chromebook 14 CB3-431 (Edgar)

Note: This article assumes the reader is willing to replace ChromeOS with Arch Linux.

The following article briefly explains all necessary procedures to install a fully-functional Arch Linux configuration on the Acer Chromebook 14 cb3-431 (Edgar).

Write Protection

Option with SeaBios

Write Protection does not have to be voided to follow the guideline of using SeaBios.

Option with coreboot

An another option would be by using the third party coreboot Script where you need to disable write protection by removing the screws nearby the wifi chip and battery which are market with a white arrow first.

Developer Mode

Prior to the installation, certain actions must be taken to grant bios reading permission on unsigned installation mediums. This includes enabling Developer Mode^{[dead link 2024-07-30 ⓘ]}, and flashing a custom SeaBios or coreboot.

Warning: Enabling Developer Mode will wipe all of your data.

Enabling Developer Mode:

1. Enter recovery mode by pressing the power button while holding down Esc+F3 (Refresh).
2. Once greeted in recovery mode (large yellow exclamation mark) press Ctrl+d.
3. You will be prompted for confirmation, press enter to confirm developer mode.
4. The device will reset and greet the user with a warning screen on every boot, that can be skipped by pressing Ctrl+d.

Flashing a custom SeaBios

See Chrome OS devices/Custom firmware#Flashing the custom firmware.

Select option 1 to Install RW_LEGACY, permitting booting from an external installation media from SeaBios.

Before selecting the reboot option and proceeding to the next part, ensure a USB flash installation medium is inserted.

Flashing with the Coreboot Script

Download the file with cd;curl -LO mrchromebox.tech/firmware-util.sh , view it: cat firmware-util.sh , and run the script sudo install -Dt /usr/local/bin -m 755 firmware-util.sh && sudo firmware-util.sh to execute the script. Choose the option of

Install/Update UEFI (FUll ROM) Firmware  

When the installation is finished you can reboot, where you have UEFI with coreboot.

Installation

Booting the Installation Media

Using SeaBios

During the white "OS verification disabled" screen, toggle Ctrl+l to enter SeaBios. Then press the Esc key to load the boot menu, and select your external installation media.

Unless the installation media runs on a Linux version 4.8.14 or prior, the internal keyboard, sound, and trackpad will not function during the installation. From this point on, proceed with the official Arch Linux Installation Guide.

Note: If SeaBios has immediately attempted to load from the internal disk, or simply ignored the Esc key boot menu request, the device has been fully shut down prior to the SeaBios load. SeaBios must be entered on reboot from ChromeOS to enter the Boot Menu

Using Coreboot

In default it would boot into UEFI if you have no OS which supports UEFI on the drive which includes ChromeOS. In UEFI you can select the USB flash installation medium.

Post installation

Unless RW protection has been voided and SeaBios has been set to boot as default, booting into grub is only possible by toggling Ctrl+l during the white "OS verification disabled" screen on boot.

Fixes

Sound

See ALSA firmware.

Internal Keyboard

The internal keyboard should be fully functional when using the latest kernel, with the exception of the top row hotkeys which are mapped to the function keys by default. See Chrome OS devices#Hotkeys for methods to implement the Chrome OS keyboard hotkeys.

Trackpad

To fix trackpad pressure sensitivity issues for the xf86-input-synaptics driver, add the following configuration file under /etc/X11/xorg.conf.d/10-synaptics.conf

/etc/X11/xorg.conf.d/10-synaptics.conf

Section "InputClass"
	Identifier "touchpad catchall"
	Driver "synaptics"
	MatchIsTouchpad "on"
	MatchDevicePath "/dev/input/event*"
	Option "FingerLow" "1"
	Option "FingerHigh" "5"
EndSection

To fix trackpad sensitivity issues when using the libinput driver, add the following local device quirk under /etc/libinput/local-overrides.quirks

/etc/libinput/local-overrides.quirks

[Touchpad pressure override]
MatchUdevType=touchpad
MatchName=*Elan Touchpad
MatchDMIModalias=dmi:*svnGOOGLE:*pnEdgar*
AttrPressureRange=4:3

After the XServer has been restarted, the changes will take place.

When using hibernation (Suspend and hibernate#Hibernation) an issue may be encountered where the module required for the touchpad elan_i2c is not loaded on resuming, meaning that the touchpad will not be operable. A workaround for this is to enable the required module during the initramfs stage.

/etc/mkinitcpio.conf

MODULES=(... elan_i2c ...)

After the recreating the initramfs image and rebooting the touchpad should now be working on resuming from hibernation.