F21 on UEFI

[Chris Murphy]

Also, some possibly related bugs:
SecureBoot enabled causes Win 8 UEFI to not start from grub
https://bugzilla.redhat.com/show_bug.cgi?id=1170245#c23

After a BIOS install of Fedora to a hard disk containing a UEFI
install of Windows 8, the Windows 8 install fails to boot
https://bugzilla.redhat.com/show_bug.cgi?id=971255

In particular dual boot scenarios, mixing UEFI and BIOS installations
is fraught with problems. Some people manage to get it to work. They
lucky or have esoteric knowledge. For sane mortal people, I suggest
keeping it UEFI+GPT only for all installed OS's; or BIOS+MBR only for
all installed OS's. At least for Fedora, it's really not practical to
support mixed installations. There are just too many things that can
go wrong, the on-disk layout is a mess... and while all of that should
be self-describing and should work if everyone followed the specs, the
reality is, it's a pain.

Pretty much UEFI (with or without Secure Boot enabled) should just
work. And if there are problems, they're bugs we need to try to fix.
Some bugs are installer, kernel, or bootloader bugs. Many bugs are
firmware bugs. But it's important to file good clean bug reports or
this stuff isn't going to get better any faster.

(A tiny point is that some firmware can tolerate BIOS+GPT, meanwhile
others faceplant, so either just use MBR or be prepared to test GPT.)

Chris Murphy