Re: Does grub-efi support chainloading legacy bios bootloaders

[Z C]

I'd like to know if the developers have any plan to support this feature officially in the future ? If so, when will it probably be implemented?

I think this feature is very useful, since some people have multiple OSes installed in multiple disks, and those OSes may have mixed BIOS/UEFI boot types.

Without this feature, people have to go to the motherboard setup page to switch the BIOS/UEFI mode everytime he/she wants to switch to a different OS.

thanks

On Mon, Jun 2, 2014 at 12:01 AM, Andrey Borzenkov <address@hidden> wrote:

В Tue, 13 May 2014 09:32:57 +0800
Z C <address@hidden> пишет:

> rEFInd has this feature: It can load a bios bootloader despite running in
> uefi mode.
>
> I consulted grub documentation, and it doesn't mention whether grub
> supports this feature. So it seems grub lack this feature. If grub
> officially doesn't provide this functionality, how can I implement it
> manually? Is it possible to do some coding and add a new module to grub-efi
> so as to chainload bios bootloaders?
>

No, grub right now does not support it. Checking UEFI specs, it defines
how UEFI system can initiate legacy boot, so yes, it should be possible
with some coding (modulo vendor implementation bugs). Actually it does
not require large amount of coding at all.

> Loading a bios bootloader when running in efi mode is very useful: In some
> cases, people has a major harddisk with os installed in efi mode, besides
> he has a secondary mobile disk with a rescue os installed in bios mode. If
> he uses grub, everytime he switches beetween the two os'es in the two
> disks, he has to go to the motherboard settings to change the boot mode. It
> is pretty inconvenient. So I hope grub will support it officially in the
> feature releases.
>
> BTW, when will the stable version of grub 2.02 release? Do you have any
> release plan (i.e. how often is grub stable version released)?