Re: grub-mkconfig os-prober did not update UUID

[Jimmie Mayfield]

Hello,


When attempting to install grub onto a different hard drive (perhaps 
rescue-mounted from another machine), it's best to bind-mount /proc, 
/dev (and possibly /sys and /run depending on what you need to do during 
the rescue) into the chroot.  I've had to do this on occasion when a bad 
grub update renders one of my machines unbootable.

For simplicity, assume that /dev/sdz1 is the /boot partition of the 
target drive and /dev/sdz2 is the / partition...

1. mount /dev/sdz2  /mnt/rescue
2. mount /dev/sdz1 /mnt/rescue/boot
3. mount --bind /dev /mnt/rescue/dev
   mount --bind /proc /mnt/rescue/proc
4. chroot /mnt/rescue
5. now run grub-mkconfig, install RPMs, etc
6. exit chroot
7. umount /mnt/rescue/dev /mnt/rescue/proc /mnt/rescue/boot /mnt/rescue


On 9/5/20 10:14, Claude Robitaille wrote:
> I understand the fact that the foreign grub.cfg is used as a source; but if the 
> UUIDs for the other non kernel command line items are changed why not changing 
> the command line itself, if the UUID matches? I understand that some menuentry 
> may be special and have very weird kernel command lines but by matching the 
> UUID value all shold be good.
>
> Changing the original grub.cfg  can not be done with grub tools; chroot and 
> then run grub-mkconfig fails due to lack of a valid /dev and possibly other 
> missing proc entries. Reverting to manually modify it can be done on the 
> grub.cfg in the new partition.