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:
www.protectedtext.com/chromeos-to-ubuntu
password: 123

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

I’ve moved this to the https://community.ubuntu.com/c/support-help-requests 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.