core.img was compiled on Linux Debian 7.7.0 x64, using gcc-multilib 4.7.2, from
the grub2 2.00-22 Ubuntu source package (https://launchpad.net/ubuntu/+source/grub2/2.00-22)
and using the guide from http://pete.akeo.ie/2014/05/compiling-and-installing-grub2-for.html
(with exFAT module removed due to size constraints).