Re: BIOS/GPT with bios_gub raw partition: core image is too big

[moo can]

 Hello,
Andrei, Pascal, Thank you for your kind answers.I tried to find references 
about size limitation but don't find anything about BIOS/GPT, always BIOS/MBR 
and thank you for the link to the Grub manual.
So if I understand well this is a limitation for i386-pc BIOS even with a GPT 
partition.

I'm trying to use grub-mkstandalone for this BIOS/GPT computer because I need 
supplemental Grub2 modules related to crypto, fs, as cryptomount, cryptodisk, 
luks, gcry_sha256, gcry_sha512 and lvm, ext2 but with at_keyboard, keylayouts 
and my keyboard layout gkb file (to type password with accented characters at 
startup which is impossible with US keyboard layout).
The default core.img generated with grub-install at install time include some 
of these modules but does not include keyboard layout related modules and gkb 
file.

I have a working core.img made with grub-mkimage and deployed with 
grub-bios-install but which is very very light so I was hoping that as I was 
using a GPT partition with a good size to host the whole core.img and no MBR I 
could include all module that I need. Now I understand why 1 MiB for the GPT 
partition is more than enough.
I made the same things for efi x86_64 laptop to generate an .efi file so I was 
hopping to do same thing for BIOS/GPT.
Is there any way to "bypass" this limitation or should I stick with my little 
working core.img which is better than nothing?
Regards


    Le samedi 20 février 2021 à 06:24:22 UTC+1, Andrei Borzenkov 
<arvidjaar@gmail.com> a écrit :  
 
 20.02.2021 01:37, Pascal Hambourg пишет:
> 
>> When I use grub-mkstandalone to generate the core.img
>> grub-mkstandalone -O i386-pc -o core.img --modules= ....
>>
>> I have : core image is too big (0x185161 > 0x78000)
>> Is it possible to "bypass" this size limitation or is it hardcoded in
>> i386-pc format even if the grub_bios raw partition exist ?
> 
> I do not think that the BIOS boot partition size is relevant to
> grub-mkstandalone. Check
> <https://www.gnu.org/software/grub/manual/grub/grub.html#Core-image-size-limitation>
> 
> I guess that somehow the core image must fit within the ~640 KB x86 real
> mode memory.

Correct. core.img must all fit in real mode memory on PC compatible system.

> But why do you want to use grub-mkstandalone instead of grub-install ?
>