Actually, Microsoft has provided a patent grant[1][2][3] to anybody who implements a FAT driver for the purpose of booting UEFI. Which is actually a reason why FAT is still in the Linux kernel even though people argue that Microsoft will sue one day.

But IMO we should be all switching to CoreBoot (or LibreBoot). It's much less fucked up than UEFI, the only negative being that you have to flash it yourself (unless you buy a $1000 5-year-old Thinkpad).

[1]: http://download.microsoft.com/download/1/6/1/161ba512-40e2-4...