Chromebooks use Coreboot firmware with a specialized payload called Depthcharge. This bootloader is customized for ChromiumOS and doesn't boot Linux/Windows.
To install Linux/Windows on a Chromebook, you have to flash this firmware, usually replacing it with Coreboot with the Tianocore payload, which is a bootloader capable of booting other OS's. (MrChromeBox supplies this custom firmware for lots of devices)
Awesome work. Have you guys looked into potential differences between the captive browser applet and the share applet, which opens when you try to share an image from your album to Facebook? The share applet is locked down to what seems to be a whitelist of URLs it can access.
I noticed on the share applet, there is a JavaScript object: window.nx that exposes some internal functions. However, I have had no luck actually calling those functions. If you want to know more about this, I can show you how I execute JavaScript on it and give you a list of window.nx functions
To install Linux/Windows on a Chromebook, you have to flash this firmware, usually replacing it with Coreboot with the Tianocore payload, which is a bootloader capable of booting other OS's. (MrChromeBox supplies this custom firmware for lots of devices)