After completing these steps you will be able to switch to ChrUbuntu from Chrome OS by simply entering the command ubuntu in the terminal. You will be able to switch to Chrome OS from ChrUbuntu by entering the command chromeos in the terminal.
2. Boot into Ubuntu and navigate to the Home folder
3. Press ctrl + h
4. Double-click the file .bashrc
5. Scroll to the bottom of the file and add this command:
alias chromeos='sudo cgpt add -i 6 -P 0 -S 0 /dev/sda;sudo reboot'
6. Save the file and close it
7. Open a terminal by selecting Applications > Accessories > Terminal and type chromeos
8. After entering your password (the default password is ‘user’), the computer should reboot into Chrome OS
9. Log in to Chrome OS and press ctrl + alt + → (→ is the forward arrow where the F2 key would normally be)
10. Type chronos and press enter
sudo vim .profile
and press enter
in chromeos, after adding the alias the ‘ubuntu’ alias command in terminal didn’t work in chromeos until a hard reboot, then afterwards it did.
sudo vim .bashrc
and put the alias there near the bottom with the other aliases – works right away for me.
12. Press the letter a to begin ‘insert mode’
alias ubuntu='sudo cgpt add -i 6 -P 5 -S 1 /dev/sda;sudo reboot'
14. Press esc to return to ‘command mode’
15. Press shift + z then shift + z again to save the file and return to the terminal
16. Type exit and press enter
17. Type chronos to log in again and press enter
18. Type ubuntu and press enter
19. The computer should reboot into Ubuntu
Sources: http://www.chromeoslounge.com/cr-48-chrome-notebook/548-easy-way-install-ubuntu-cr-48-a-8.html#post9580 and http://www.chromeoslounge.com/cr-48-chrome-notebook/548-easy-way-install-ubuntu-cr-48-a-9.html#post9711
Note about the Chrome alias, it only works in the developer “chronos” console (/.profile) unless you add instead to ~/.bashrc, and you can name it whatever you want. On the Ubuntu side, another option is to add a desktop icon that runs the cgpt command.