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ctralie/GalliumOS on Edgar.markdown

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Created April 19, 2024 17:09
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Guide to installing GalliumOS on an Acer Chromebook 14" (CB3-431) 'Edgar'
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GalliumOS on Edgar.markdown

These directions have been adapted from https://gist.github.com/stupidpupil/1e88638e5240476ec1f77d4b27747c88?permalink_comment_id=2198481

For more info on some of these steps, visit https://mrchromebox.tech

First boot

  • Connect the power
  • Open the lid

You might want to at least proceed through wifi setup and check that the hardware is working correctly.

Enable Developer mode

In this section you will put your Edgar into 'Developer Mode' which will 1) disable 'verified boot', allowing you to run operating systems that haven't been signed by Google, and 2) give you access to a root shell in Chrome OS.

This will wipe all your data on your Edgar.

See the Chrome OS generic information for entering Developer mode or How-To Geek's guide for more information.

  • Having shutdown your Edgar, hold down the Esc and Refresh (↻) keys and press the Power key.

  • Your Edgar will then boot into Recovery Mode and appear to warn you that "Chrome OS is missing or damaged."

  • Press Ctrl-D.

  • The screen will change to one saying “To turn OS Verification OFF, press ENTER”.

  • Press the Enter key and your Edgar will reboot.

  • Your Edgar will boot to a screen that says “OS verification is OFF”. If you wait, your Edgar will eventually beep several times and then boot to Chrome OS; alternatively, you can press Ctrl-D at this point to immediately boot to Chrome OS.

  • Your Edgar will show a warning about transitioning - wait.

  • Your Edgar will show a screen saying that it is "Preparing your system for Developer Mode". This process will take some time. A progress bar is displayed at the top of the screen.

  • Eventually your Edgar will reboot one more time.

  • Your Edgar will boot to a screen that says “OS verification is OFF”. If you wait, your Edgar will eventually beep several times and then boot to Chrome OS; alternatively, you can press Ctrl-D at this point to immediately boot to Chrome OS.

At this point, Developer mode is enabled and OS verification has been disabled. It will continue to show the “OS verification is OFF” screen at startup.

Disabling Write Protect

You will have to physically open up your Edgar in this section, see the iFixit teardown of an Edgar for more information and photos.

N.B. The iFixit source is actually wrong on one quite important point - only the screw near the battery needs to be removed. (I didn't suffer any ill-effects from removing, and replacing, both.)

Remove the write-protect screws

  • Shutdown your Edgar.

  • Remove the 8 shorter and 2 longer screws from the underside of your Edgar.

  • Remove the bottom panel of your Edgar.

  • Locate the two write-protect screws and remove them. (See the iFixit teardown.)

  • Replace the bottom panel of your Edgar. (I suggest you can safely leave the screws out for now, if you're careful.)

Update the firmware to enable Legacy Boot

The firmware that your Edgar comes with does not properly support booting operating systems other than Chrome OS. In this section you will update the RW_LEGACY section of your Edgar's firmware and configure it to allow 'Legacy Boot'.

Update: As of February 2018, Mr Chromebox has produced a UEFI Full ROM firmware for Edgars, and other Braswell Chromebooks. This is considered a better option than updating RW_LEGACY if you are no longer interested in using Chrome OS at all on your Chromebook and are using GalliumOS 2.2 or later. This guide still describes updating RW_LEGACY and allowing dual-booting with Chrome OS.

This section relies on the work of Mr Chromebox. See MrChromebox.tech for more information, in particular the Firmware Utility Script section.

  • Boot your Edgar to Chrome OS.

  • Proceed to setup wifi.

  • Press the 'Browse as Guest' button toward the bottom-left corner of the screen.

  • Hold down the Ctrl and Alt keys, and press T, to get a crosh terminal.

  • Type shell and press the Enter key to get a regular shell in that terminal.

  • Type (or copy-and-paste) cd; curl -LO https://mrchromebox.tech/firmware-util.sh && sudo bash firmware-util.sh and press the Enter key to download and run the Mr Chromebox Firmware Utility Script.

  • Type 2 and press the Enter key to choose "Install/Update UEFI (Full ROM) Firmware".

  • Type y and press the Enter key again to confirm

  • Type Y to continue after the scary warning about not being able to boot chrome again

  • You can skip creating a backup of the firmware, and then shut down the computer

At this point, your Edgar has been configured to boot from USB drives and install other operating systems

Install image

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