SOLVED: Issue with Centos 8 and GRUB

Issues related to applications and software problems and general support
Post Reply
pjc123
Posts: 79
Joined: 2010/08/17 16:59:11
Contact:

SOLVED: Issue with Centos 8 and GRUB

Post by pjc123 » 2020/07/13 12:49:23

MY SETUP BEFORE UPGRADING TO CENTOS 8:

I had two operating systems on a single drive on my laptop:

Centos 7
Linux Mint 19

The GRUB menu was controlled by Centos 7, which I used to select which operating system to load.

In order to update kernels on each operating system I would do the following:

1) First I would upgrade the kernel on Linux Mint and register it with the local OS with the following commands:
sudo update-grub
sudo update-grub2

2) Then if necessary I would upgrade the kernel on Centos 7. However, for the upgraded kernels from Linux Mint to show up in the GRUB menu on Centos 7, I had to run the following commands:

sudo grub2-mkconfig -o /boot/grub/grub.cfg
sudo grub2-mkconfig -o /boot/grub2/grub.cfg

I am not sure if it is grub or grub2 that adds the kernel to the menus, but it didn't hurt to run both.

FAST FORWARD TO CENTOS 8

The only command that even runs on the Centos 8 side now is the following:

grub2-mkconfig -o /boot/grub2/grub.cfg

AND THE RESULT IN THE TERMINAL IS (sdb contains the two OS's):

Generating grub configuration file ...
/dev/sdb: open failed: No medium found
/dev/sdb: open failed: No medium found
/dev/sdb: open failed: No medium found
/dev/sdb: open failed: No medium found
/dev/sdb: open failed: No medium found
/dev/sdb: open failed: No medium found
/dev/sdb: open failed: No medium found
/dev/sdb: open failed: No medium found
Found Windows 10 on /dev/nvme0n1p1
done

AND NOT ONLY DOES THE NEW LINUX MINT KERNEL SHOW UP IN THE GRUB MENU, BUT LINUX MINT DOES NOT SHOW UP AT ALL, SO I HAVE NO WAY TO LOAD IT.

So, my question is.....what has changed and how do I fix this?

Thanks,

PJC
Last edited by pjc123 on 2020/07/14 17:00:10, edited 1 time in total.

pjc123
Posts: 79
Joined: 2010/08/17 16:59:11
Contact:

Re: Issue with Centos 8 and GRUB

Post by pjc123 » 2020/07/14 16:59:55

SOLVED: I saw where someone else startied to have the same problem. Apparently it is necessary to mount the the Linux Mint OS before running the grub2-mkconfig command. I never had to do this before (perhaps it was automatically mounted before?).

On another topic, I also found why the following error occurs:

/dev/sdb: open failed: No medium found

It has to do with the smart card reader and I applied the fix here:

https://bugs.launchpad.net/ubuntu/+sour ... ug/1834250

Post Reply

Return to “CentOS 8 - General Support”