[Buildroot] Boot process stuck at "GRUB loading.." since 2021.02.1

[Peter Seiderer]

Hello Stefan,

On Mon, 11 Oct 2021 17:29:19 +0000, "Walter, Stefan" <stefan.walter at iml.fraunhofer.de> wrote:

> Hi,
>
> > > Maybe try to 'bisect' the problem as you mentioned it worked before
> > > 2021.02.1 (did you test 2021.02.0?), not much grub related patches in
> > > between...
> >
> > Buildroot 2021.02(.0) does boot, the following releases on the 2021.02.x
> > branch don't. I just tested 2021.08 with the same configuration file, and it
> > doesn't boot, either.
> >
> > I haven't actually bisected, yet, but looking at the commit log, ...
> >
> > >   e840f2d469 boot/grub2: Backport 2021/03/02 securify fixes
> >
> > ...this looks like the most likely culprit, because it's the only commit to
> > boot/grub2 I see that makes any changes to the GRUB sources between
> > 2021.02 and 2021.02.1.
>
> I can now confirm that this is the commit that introduced the problem. What baffles me is that you say you have a working configuration using GRUB and i386. Could you send it to me or try mine for comparison?

Can you try instead of your original

/path/to/buildroot-sdk/host/bin/grub-mkimage \
	--config=grub_early.cfg \
	--directory=/path/to/buildroot-sdk/host/lib/grub/i386-pc \
	-o ./genimage_input_tmp/grub_core.img \
	--format=i386-pc \
	--prefix==/boot/grub \
	biosdisk part_msdos ext2 normal linux configfile

the following one (makes the difference here for me with the qemu test):

/path/to/buildroot-sdk/host/bin/grub-mkimage \
	--config=grub_early.cfg \
	--directory=/path/to/buildroot-sdk/build/grub2-2.04/build-i386-pc/grub-core \
	-o ./genimage_input_tmp/grub_core.img \
	--format=i386-pc \
	--prefix==/boot/grub \
	biosdisk part_msdos ext2 normal linux configfile

Note the --directory change from the '.../host/lib/grub/i386-pc' (installed) directory to
'.../build/grub2-2.04/build-i386-pc/grub-core' build directory (as the original buildroot
grub2 install step uses to create images/grub.img...

Suspect the host/lib/grub/i386-pc provided modules are from the build/host-grub2-2.04 build
(instead of the build/grub2-2.04 for the target) and therefore without the '-Os' fix
(or they are mangled during the install step)...

Regards,
Peter

>
> Best regards,
> Stefan