I followed similar yet somewhat modified approach to develop omaha_cros_update.sh script which can be used to update regular PCs to the latest version of Chrome OS. And when another update is installed, it is installed at ROOT-A, and again, you boot from ROOT-A partition (you get the idea). So, until you install another update, this partition is the one you boot from. When you update for the first time, the update is installed at ROOT-B partition. On a regular installation, ROOT-A partition is actually the root partition you boot from, and ROOT-B partition is only used when you update your Chromebook from About Chrome OS page. How to revert back if something goes wrongĬhrome OS has two root partitions namely ROOT-A and ROOT-B (partition numbered 3 and 5 respectively).Please, install using the installer found in the latest release instead of the one given here. NOTICE: The main repository became unstable once again.