I have full Linux installed on my flash drive. What I want to do is boot from this flash drive with the Asus C300 Chromebook.There are many tutorials in the Internet on how to install Linux on  chromebook, but I want have the original system untouched. All tutorials note that I have to enable developer mode on chromebook, but I'm curious if it is necessary to such simple task as booting from flash drive. So my question is, how to go to multiboot on chromebook, something like pressing F12 on my laptop?
Boot Linux on Chromebook from external media
boot;chrome book;chrome os