[OM Cooker] Failed to install Grub2.

[Ben Bullard via OM-Cooker]

When trying to install OMLx on a new ASUS X550C notebook installer gives 
this error.

Failed to install Grub2. Inappropriate ioctl for device
Try anain?
How can I get around this?

The computer has uefi or efi (not sure which is correct) boot.

Thanks,

ben79