Fedora x64 does indeed work after the BIOS 1.07 upgrade. I still can't figure out why Arch Linux doesn't boot though. Arch is 4.8.11 and Fedora boots with both 4.8.6 and 4.8.13 so I doubt it's the kernel version. UEFI/legacy boot also doesn't seem to make a difference since Fedora boots with both.
Arch usually has a very vanilla kernel, so either Fedora and Ubuntu both have a kernel patch that affects this or I'm missing something else...
@stavros: you can have UEFI with secure boot disabled if you set a supervisor password. However, it seems like choosing "Legacy" still allows UEFI boot as well.