Re: Does grub-efi support chainloading legacy bios bootloaders

[Andrey Borzenkov]

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)?