Updating grub after dnf-system-upgrade

[Jeffrey Walton]

Hi Everyone,

I just dnf-upgraded my last system from F37 to F38. One of the
post-upgrade task is "Update GRUB bootloader on BIOS systems"
(https://docs.fedoraproject.org/en-US/quick-docs/dnf-system-upgrade/):

Systems with the BIOS firmware have the GRUB RPM packages updated.
    However, the installed or embedded bootloader is never updated
    automatically. It is a good idea to update it between Fedora release
    versions.

I have a system that is is using BIOS, and it not using UEFI or
SecureBoot (though UEFI is available):

$ sudo dmidecode | grep -i -E 'BIOS|UEFI'
    Getting SMBIOS data from sysfs.
    SMBIOS 3.0.0 present.
    BIOS Information
                BIOS is upgradeable
                BIOS shadowing is allowed
                BIOS ROM is socketed
                BIOS boot specification is supported
                UEFI is supported
        BIOS Revision: 1.0

$ mokutil --sb-state
    SecureBoot disabled
    Platform is in Setup Mode

When I run the command:

$ sudo mount | grep "/boot "
    /dev/mmcblk0p2 on /boot type ext4 (rw,relatime)

Do I install grub2 on /dev/mmcblk0 or /dev/mmcblk0p2? I think it is
the former, but I want to make sure. That is, is this correct:

sudo grub2-install /dev/mmcblk0

(I have open questions about systems that claim both BIOS and UEFI,
but I have not been able to find answers. If I need to back up a bit,
then please say so).

Thanks in advance.

[Samuel Sieb]

On 4/26/23 22:47, Jeffrey Walton wrote:
> I just dnf-upgraded my last system from F37 to F38. One of the
> post-upgrade task is "Update GRUB bootloader on BIOS systems"
> (https://docs.fedoraproject.org/en-US/quick-docs/dnf-system-upgrade/):
>  Systems with the BIOS firmware have the GRUB RPM packages updated.
>  However, the installed or embedded bootloader is never updated
>  automatically. It is a good idea to update it between Fedora release
>  versions.
>
> I have a system that is is using BIOS, and it not using UEFI or
> SecureBoot (though UEFI is available):
>
> When I run the command:
>  $ sudo mount | grep "/boot "
>  /dev/mmcblk0p2 on /boot type ext4 (rw,relatime)

If it was UEFI, there would be a /boot/efi mount as well.
> Do I install grub2 on /dev/mmcblk0 or /dev/mmcblk0p2? I think it is
> the former, but I want to make sure. That is, is this correct:
>  sudo grub2-install /dev/mmcblk0

Yes.
> (I have open questions about systems that claim both BIOS and UEFI,
> but I have not been able to find answers. If I need to back up a bit,
> then please say so).

Not sure what you mean by that.  The system can support both options, 
but only one will be active at a time.

[Tom Horsley]

On Thu, 27 Apr 2023 01:47:58 -0400
Jeffrey Walton wrote:
> (I have open questions about systems that claim both BIOS and UEFI,
> but I have not been able to find answers. If I need to back up a bit,
> then please say so).

This may or may not be helpful, but when I make a "universal" boot
USB stick these are my notes for installing both bios and uefi grub:

mount /dev/sdc1 /mnt
mkdir /mnt/boot
grub2-install --target=i386-pc --recheck --boot-directory=/mnt/boot /dev/sdc
grub2-install --target x86_64-efi --removable --boot-directory=/mnt/boot --efi-directory=/mnt