Before you can install Linux on the c100p you must put the device into “Developer” mode. Developer mode essentially resets the c100p and unlocks the device.

• Shutdown the device
• To invoke Recovery mode, you hold down the ESC and Refresh keys and press the Power button
• At the Recovery screen press <CTRL> D. Note: there's no prompt - you have to know to do it
• Confirm switching to developer mode by pressing enter, and the laptop will reboot and reset the system. This takes about 15-20 minutes
• After enabling developer mode - At the “OS Verification is off” screen - you will need to press:
  • <CTRL> D to boot to legacy ChromeOS
  • <CTRL> U to boot to Linux
• To hard reboot the c100p in case of lockup Hold Refresh button and press the Power button

• Sign back into your c100p
• Open Chrome
• Open a crosh shell using <CTRL><ALT> T and type:

shell
sudo su
crossystem dev_boot_usb=1 dev_boot_signed_only=0

• Reboot the system to allow the change to take effect. Use <CTRL> D to go to the original Chrome OS
• Shut down the system

You now have developer mode enabled on your c100p. Be mindful of the <CTRL> D <CTRL> U boot options outlined above.