Grub2-mkconfig RL9.3 fresh install bug

[Jenns]

I just noticed this bug in rocky linux 9.3

grub2-mkconfig -o /boot/efi/EFI/rocky/grub.cfg not working as inteneded, like in previous versions.

I edit this file /etc/default/grub to add for example intel_iommu=on to the GRUB_CMDLINE_LINUX like so.

GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR=“$(sed ‘s, release .*$,g’ /etc/system-release)”
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT=“console”
GRUB_CMDLINE_LINUX=“crashkernel=1G-4G:192M,4G-64G:256M,64G-:512M rd.lvm.lv=rl/root intel_iommu=on”
GRUB_DISABLE_RECOVERY=“true”
GRUB_ENABLE_BLSCFG=true

The I run grub2-mkconfig -o /boot/efi/EFI/rocky/grub.cfg like usual, all goes ok, then when I reboot the machine and look at the grub command with “e”

The grub doesn’t get updated with my changes, I tried this with RL9.2 and it’s working correctly, fresh install of RL9.3 doesn’t work, and if you update from 9.2 to 9.3 it stops working.

Way to reproduce:

Install a fresh copy of RL9.3 minimal with all the defaults, change the values in /etc/default/grub then run grub2-mkconfig -o /boot/efi/EFI/rocky/grub.cfg reboot the machine wait for the grub bootleader menu to load press “e” to edit then notice that your changes are not there.

Thanks I’ll try to find a workaround so far only works in 9.2 and my changes do stay if I add the changes in 9.2 then update to 9.3, not sure what could be happening here.

Thanks

[Jenns]

Looking at the grub.cfg file I can see the changes are there.

[Ritov]

Grub config was “normalized” for non-efi and efi systems. Use

grub2-mkconfig -o /etc/grub2.cfg

[Jenns]

Oh I see the symlink has changed location

I’ll try this.

Thank you

[Ritov]

BTW, its good practice to not upload pictures. Instead include the content as preformatted text, that allows to be found when searched …

[nazunalika]

What you’re experiencing won’t be a bug. If the suggested command does not work for you still, consider adding --update-bls-cmdline. You may also want to consider using grubby instead.

grubby --update-kernel=ALL --args='...'

See below for context.

https://bugzilla.redhat.com/show_bug.cgi?id=2203203

https://bugzilla.redhat.com/show_bug.cgi?id=2212320

https://fedoraproject.org/wiki/Changes/BootLoaderSpecByDefault

https://fedoraproject.org/wiki/GRUB_2

[hmg]

BS"D
I experienced the same problem. Even updating /etc/grub2.cfg did not work for me until I added the extra argument mentioned by nazunalika

grub2-mkconfig --update-bls-cmdline -o /etc/grub2.cfg

That worked.
Thanks!

[jlehtone]

@Jenns

Oh I see the symlink has changed location

Indeed.

In el8 (and el7) the grub.cfg is in /boot/efi/EFI/${VENDOR}/ for EFI system and in /boot/grub2/ for legacy system.
If el9 the actual grub.cfg is in /boot/grub2/ for both, and EFI system has in /boot/efi/EFI/${VENDOR}/ a stub that you don’t want to change after install. An example stub:

search --no-floppy --fs-uuid --set=dev 14fba..5e95
set prefix=($dev)/grub2

export $prefix
configfile $prefix/grub.cfg

where 14fba..5e95 is UUID of the filesystem that has the content of /boot/.
Hence the last line is effectively: configfile /boot/grub2/grub.cfg

One can restore the stub by setting correct UUID (that both blkid and lsblk -f do show) to sample above.

---

The grub2-mkconfig does apparently follow symlinks, because it can modify grubenv and BLS entries and the former is with actual grub.cfg.

[Jenns]

I tried doing grub2-mkconfig -o /boot/grub2/grub.cfg and It did not work, what is the best practice to modify this, seems like things change much. Thank You

My bad sorry I missed this grub2-mkconfig --update-bls-cmdline -o /boot/grub2/grub.cfg this works.