It has nothing to do with the OS. It's all in the firmware. There are firmware hacks out there that will take the region limits off. I don't see any problem with doing this if it's legitimate. Use them at your own risk though. If...
TechIMO Forum Link. Great tech help site.
I believe this is what you're looking for though: http://www.intel.com/support/chipsets/iaa/settings.htm
Let me know if these links helps you.