How to install Ubuntu on a Chromebook (Lenovo 100S)

I had very big troubles installing Ubuntu on my chromebook.
My primary goal was to overwrite chromeOS with Ubuntu, but no tutorial I found worked all the way.

I had to go through multiple tutorials and I had to install Ubuntu in 4 different ways until it finally worked.

Here are all the steps I took to achieve Ubuntu on my chromebook.

I first had to enter Developer mode and disable os verification, but in the end the tutorial told you to hit ctrl + L and you would enter the bios. I did this to be able to boot from a usb drive to be able to install ubuntu, but when I hit ctrl + L the chromebook only beeped at me, and even after I enabled usb booting and hit ctrl + U it beeped and flashed a black screen but then just went back to the “os verification is off” screen.
To bypass this I had to install SeaBIOS via the terminal you can access by pressing ctrl + alt + T when inside the chrome browser in Developer mode.
Inside SeaBIOS installation I choose “Modify Boot_Something” I don’t remember what it said exactly but there were only two options that had “Boot” in it and one of them said “Modify” and I chose that one.
Then I rebooted my chromebook and could successfully boot from my usb drive. But after the installation, SeaBIOS couldn’t found a bootable device even after 4 re-installations, so I tried something different. I followed a tutorial on how to install Ubuntu on a usb drive instead of a hard disk. And it worked. While trying to install Ubuntu on the hard disk I also removed the write-protect screw on the motherboard which is located next to the usb port on the left side of the motherboard under a white sticker that says “Lenovo”. It’s located differently on different chromebooks.
My chromebook also refused to start once during the process for unkown reasons, but I think it had something to do with the re-instalations of ubuntu, and to fix this, you just unplug the battery from the motherboard and plug it in again.

Here are all the tutorials I followed to achieve this:
Apparently I can only post 2 links as a new user so go here for all the links:
password: 123

Hope this helps anyone who also wants chromeOS to f**k off from their computer.

I’ve moved this to the category because this site isn’t designed to take tech support questions. Sorry. I’d recommend using one of the official support channels listed on the Finding Help page.