These are my notes on installing Arch Linux on a Dell Chromebook 11, model 3189.
I took off the backing and unscrewed the write protection screw. The screws on the back are stuck to the backing which was neat. The plate itself required some prying to pop off. The WP screw was marked pretty clearly on the chromebook.
Getting the chromebook into developer mode was a bit of a pain. I had to press the Escape button and the Refresh button. Then push the power button and let go. Hold the Escape and Refresh until the warning page shows up. Press Enter to turn off OS verification. Then press Ctrl D on the screen that asks if you want to turn OS verification on.
This should take you to the Developer Mode screen. Now this part will take awhile to actually get into Developer Mode. You will be shown the screen to turn on OS verification and pressing Ctrl D once more will put you into ChromeOS.
Use Ctrl Alt T to get crosh running. Then type in shell to get to the shell environment.
I'm not sure if developer mode is required to get to the shell.
https://mrchromebox.tech/#fwscript
Enter the following to run the firmware utility:
cd; curl -LO mrchromebox.tech/firmware-util.sh && sudo bash firmware-util.sh
I used the UEFI option to wipe ChromeOS.
Once the UEFI firmware is loaded, shutdown the machine and plug in the Arch usb. Power the machine back up and we should be seeing the MrChromebox screen. Press Escape to get to the boot manager and select the usb.
From this point on I used the regular arch installation instructions. The only difference was that the harddrive is mmcblk0 for me instead of sda or nvme.