The background is that ubuntu and, perhaps, fc6, set some options on the gcc pass that make no sense on a bios build. This is a guess. The result is a non-working linuxbios on those machines. It is believed the issue is some sort of stack protection flag that gets set.
Yeah, at least FC6 does that, and it should be reported as a bug to them (or as a serious misfeature at least) -- by default enabling some options that FSF GCC won't allow you to enable by default (for a good reason) cannot be helpful.
Does LinuxBIOS build with -ffreestanding? If you don't, that's a bug for you too -- if you do, and that option does not disable SSP, that's a GCC bug -- either a mainline GCC one, or one in FC6, depending on how they enable it by default.
Segher