How to uninstall chrome OS and install Ubuntu 16.04 fully (not Crouton) on a Chromebook [duplicate]

I want to uninstall Chrome OS and install Ubuntu instead. How would I do this?

WARNING: you cannot go back to Chrome OS. This permanently installs Ubuntu!

Things you will need:

1. A spare computer (one without Chrome OS)

2. a usb drive (must have more than 2GB worth of available space)

3. A spare keyboard and mouse

Steps:

1. This will wipe your local data, so make sure to back anything up that you don't have stored in the cloud. To put your Chromebook in Developer Mode:

   Press and hold the Esc and Refresh keys together, then press the Power button (while still holding the other two keys). This will reboot your Chromebook into Recovery Mode. As soon as you see Recovery Mode pop up—the screen with the yellow exclamation point—press Ctrl+D. This will bring up a prompt asking if you want to turn on Developer Mode. Press Enter to continue, then give it some time. It'll pop up with a new screen for a few moments, then reboot and go through the process of enabling Developer Mode. This may take a little while (about 15 minutes or so), and will wipe your local information. When it's done, it will return to the screen with the red exclamation point. Leave it alone until it reboots into Chrome OS.

   (Note that some older Chromebooks have a physical switch that you'll have to flip in order to turn on Developer Mode. If you aren't sure, look up instructions for your specific device on enabling Developer Mode.)

2. Set it up normally, then press Ctrl-Alt-T to open the crosh. Type shell then Enter to open the shell. Then type cd;bash <(curl https://johnlewis.ie/flash_cb_fw.sh) and Enter then follow the options to install new firmware. In most cases pick install Full ROM(let your computer work until given the safety prompt o restart, otherwise you could brick you computer).

3. Reboot your system. If it boots into a sea BIOS then good job! If it boots into Chrome OS(or doesn't boot) you did something wrong. For the people who got it to work turn off your chromebook. Now go to your second PC to create a Bootable Ubuntu Live USB. If you don't know how to do this then follow the guide.

4. Go back to your Chromebook with your new bootable usb, and plug it in. Turn on the chromebook and press esc when given the option and select your USB. This will boot into an Ubuntu installation screen.

5. Install Ubuntu normally and select erase other OS and install Ubuntu (Dual booting doesn't work with this method)

   Side note: Your keyboard might not work as linux does not have the drivers yet. you will need an external keyboard and mouse until you install he drivers...

see https://johnlewis.ie/custom-chromebook-firmware/rom-download/ for any updates.