Ubuntu may stop working after a Chrome OS update. If that‘s the case, update all the installed targets using the following command (in Chrome OS, open a terminal using Ctrl + Alt + T, then type "shell"):
sudosh -e ~/Downloads/crouton -u -n chrootname
Where "chrootname" is the name of the chroot you want to update. The default chrootname is the codename for the Ubuntu version you‘ve installed (regardless of the desktop environment you‘ve installed). For example, if you‘ve installed Ubuntu 12.04 Precise, the default chrootname is "precise".
