This markdown file explains how to run Ubuntu on your Acer CB3-111-C670 Chromebook from a USB 3.0 flash drive.
NOTE: We are using a USB 3.0 flash drive with Linux installed with persistent storage, since the internal eMMC storage is slower than USB 3.0.
Disable Hardware Write Protection
Remove all 12 screws from the back of the laptop and remove the rear cover. Remove the write protection screw Reassemble machine