On Feb 4, 2014, at 12:02 PM, Andrew Lutomirski <luto(a)mit.edu> wrote:
>> IMO in an ideal world, there would be one (or zero!) copy of
the
>> bootloader config, and the default configuration of the bootloader
>> would populate the ESP (with the signed shim!), the BIOS Boot
>> partition, and the (fake) MBR in the first sector. That way the disk
>> would *always* be BIOS-bootable and, as long as there's a (working)
>> copy of efibootmgr around, you can make the system UEFI-bootable with
>> a single command that doesn't write to disk.
>
> I'm not opposed to the layout, but I'm personally totally disinterested in
the ensuing clusterf|ck experiences I've already had with UEFI+BIOS dual boot
OS's. If I could only experience food poisoning instead, my disposition would be no
worse for the wear.
That's okay. I can deal with the clusterfsck all on my own, as long
as other things don't get in the way unnecessarily. :)
So the problems with this idea you have:
https://bugzilla.redhat.com/show_bug.cgi?id=1022316#c3
1.
I'm not certain it's simpler code:
if EFI, then GPT with ESP and BIOSBoot;
if BIOS, then MBR when destination < 2TB
else GPT with ESP and BIOSBoot.
If it is simpler for the anaconda team, fine then I'm neutral.
2. But for users, it's a total edge case to think of switching between BIOS and UEFI
without reinstalling, let alone actually doing it.
3. Realize there's no way for anaconda to know if the computer is UEFI booted with the
CSM. So a.) it can't use GPT for all BIOS computers, because we know from a circa
Fedora 15 release that this causes problems for some BIOS firmware; and b.) using MBR
there is no such thing as BIOSBoot, and blivet has no code for creating ESP's with
0xEF on MBR disks which also uses a valuable primary partition in the process, therefore
the request only makes it easier to convert EFI to BIOS. It does nothing for BIOS to EFI
ease of conversion.
And as I argued before, needing to convert from EFI to BIOS implies something is broken
and needs to be fixed, not fuck it up worse by converting the install to BIOS.
Chris Murphy