If you're like me, and you use your Chromebook for a bit more than browsing the web, you might be looking for a way to enable write access to your filesystem to tweak some things that you don't have access to. After doing some research I found out how and I wanted to share.
First you have to put your Chromebook into Developer Mode. To get your Chromebook into recovery mode, follow these steps.
Note: Developer mode will wipe your Chromebook clean, so back up any data you want to keep before doing this.
Step 1:
First you will need to hold the ESC and Refresh key and then press the power button. This will get you to a screen that says "Chrome OS is missing or damaged". Don't be alarmed.
Step 2:
At this point, press CTRL+D and you will be presented with another screen that says "Press enter to enable Developer Mode". Press Enter. After this it will take about 15 minutes to enter developer mode. That's it, two steps!
From this point on, when you boot your Chromebook you will need to press CTRL+D to boot into the OS or it will boot, and then make a very loud beeping before loading the OS. Be careful not to press space to re-enable root filesystem verification or you will restore your Chromebook back to factory settings!
Enable Write Access in ChromeOS
From this point on if you want to get in there and do some digging around and make modifications to your filesystem, press CTRL+ALT+T. You'll be presented with a ChromeOS shell, type 'shell' into the command line without quotes, and you'll get access to a BASH shell. After that, run the following command to enable write access to your filesystem.
sudo ./make_dev_ssd.sh --remove_rootfs_verification --partitions 2
Note that after you do this, if you ever want to take your Chromebook out of developer mode you'll need to use the Chrome OS Recovery Image to restore your installation back to defaults.
Congrats! You're one step away from unlocking your Chromebook's full potential! From here you can install another distro of Linux using Crouton, or one of my favorites, install the Chrome OS package manager Chromebrew, which is an amazing app developed by Michal Siwek. The first thing I did was install nano through Chromebrew, because I have yet to take the time to learn vim... Thank you Michal!