How to dual boot ChromeOS and Linux— a step by step guide

!!! Security Warning !!!

Part of this tutorial involves switching your chromebook to developer mode. When the chromebook is in developer mode, ChromeOS built in security features are disabled. This makes it less secure than if developer mode is switched off.

What you will need…

  • A flash drive for your Gallium installation. It doesn’t matter which one but I prefer Sandisk’s Ultra Fit. It’s small enough that it can be left in the chromebook permanently and it can be picked up for about €20/$20. I recommend a minimum size of 64GB.
  • Another flash drive for the Gallium image. This one can be as small as 2GB.
  • Access to another operating system; Windows, MAC, Ubuntu or another Linux Distro. This is just for the initial Gallium image download and burning it onto to the flash drive. This tutorial is written using examples from Windows 7, although these steps are pretty similar in other operating systems.
  • Most importantly, a chromebook.

Step 1 — Check your Hardware Compatibility

Click on this link and find your chromebook in the first column. Then read across to the fifth column to see if your chromebook is compatible. If it is you can continue to step 2.

Step 2— Enable Developer Mode

This part comes with a small caveat. When you enable developer mode, you will reset your chromebook to factory settings. This means that anything you have saved on the hard drive will be lost. You should back it up on your google drive if you want to keep it. All your chrome settings will be safe as these are saved to your google account.

Step 3 — Add Mr. Chromebox Firmware

The Mr. Chromebox script will add some bios firmware that will allow us to boot Gallium. Go to Mr Chromebox’s firmware page and copy the script (shown below) exactly as is. Don’t try and copy it by typing it out. Highlight it and press Control + C to copy.

Step 4— Download the Gallium Image

Go to the Gallium Download page and click the button that matches the CPU type that you identified in the previous step.

Step 5 — Download Etcher

Etcher is the tool that we will use to create a live USB. This live USB is what we will use to install the Gallium Operating System onto our second flash drive. Etcher is available for Windows, Mac and Linux, although all screenshots in this tutorial are shown on the Windows version.

Step 6 — Create a Live USB

Insert one of your USB flash drives into your machine. We are creating the live USB here, which will be used to create the final Gallium installation so if one of your flash drives has more memory than the other, use the smaller one.

Step 7— Beginning the Gallium Installation

Shut down your chromebook and insert both USB flash drives. Now switch it on again. When you see the white screen with the red exclamation mark press Control + L and then press Esc when prompted.

!!! Step 8 — Something Else !!!

When you see the screen below it’s very, very, very important that you change the selection to Something Else as shown below. If you don’t you will wipe ChromeOS, which is not what we want. Click continue when you’re ready to proceed.

Step 9 — Select the device for the boot loader

Just as I emphasized the importance of the last step, I cannot emphasize the importance of this one enough either. When you see the screen below you need to change the selected drive to the USB drive you’re installing Gallium onto. If you install the boot loader on your hard drive it may prevent you from booting ChromeOS. You can see below that the default selected was /dev/mmc/blk0 . We want to change this.

Step 10 — Format your USB drive

Now find your USB in the main list of drive partitions. You can see below mine is called /dev/sdb1 .

Step 11 — Create your boot partition

The following few steps will cover the various procedures involved in creating the boot partition, root partition, swap area and home partition. There is a plethora of information online if you want to read more about this and there is more than likely a better way to do it. What I’m about to show you is what works best for me and I have settled on it after a fair bit of trial and error. The idea behind making these partitions is that if part of your flash drive becomes corrupt, the whole drive will not get corrupted. It will be isolated to a single partition.

Step 12 — Format your root partition

Similarly, highlight the free space section and click on the + again. Now allocate 10,000MB to your root partition.

Step 13 —Format the swap area

Similarly, allocate 4096MB to your swap area. It is debatable whether this is actually useful or not but its better to be looking at it than looking for it.

Step 14 — Format your home partition

Allocate any remaining space to your home directory and click ok

Step 15 — Install Gallium

Click Install now as shown below

Step 16 — Identify Yourself

The Gallium installer will ask you some questions for configuring the new operating system. Go ahead and fill it out. Click continue when you’re done.

Step 17 — Sit back and relax

Take a break, you’ve earned it! Gallium will spend a few minutes installing all the necessary files on your USB flash drive

Step 18 —All done!

Congratulations, the installation has completed and your new operating system is ready to go!

Step 19 — Boot into your new OS

When your chromebook restarts you will be greeted again with the white screen and red exclamation mark. This is your new startup screen. Pressing Control + D will boot into ChromeOS and pressing Control + L will let you open the boot menu by pressing Esc


I hope the installation has gone well for you and you are now enjoying the benefits of dual booting your chromebook. Gallium is like a lightweight version of Ubuntu so most of the commands that work for Ubuntu will work for Gallium as well.



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