Comment 13 for bug 1253443

No, it's actually an out-of-range write, almost certainly just multiplied up by the sector size over 512 as you might expect. http://git.savannah.gnu.org/gitweb/?p=grub.git;a=commitdiff;h=4dedb13f51bd467f00a2da9c3611f7c00519f889 looks very promising so I'll try that next.