Commenting further -
I am trying to get it to work from a USB.
Windows 8.1 and 10 can do so, so theoretically it should work with this Haswell Chromebook.
I singled out that it is an USB issue for El Capitan as the Hard Disk is USB but also that it chokes on
Still waiting for root device
USBMC identifier (non unique), etc.
Any ideas to move on from this?
I have the DSDT for the CB, if it can help?