How can I revert back to the previous dom0 kernel?

User Support
#1

I upgraded dom0 to kernel-latest to fix a shutdown problem, but now the sound doesn’t work anymore. I have no sound coming out of the laptop! The driver and alsamixer work and I can see that sound is detected, but it’s not coming out the of the speakers.
Now I want to revert back to the previous kernel. kernel-1000:5.15… is already installed. How can I choose that now, instead of kernel-latest?

#2

This links to a section describing how to select a different kernel at boot time:

https://www.qubes-os.org/doc/how-to-install-software-in-dom0/#changing-default-kernel

1 Like
#3

Thank you for your reply.
Prior to posting my question on this forum, I had attempted
sudo nano /boot/efi/EFI/qubes/xen.cfg
My system is UEFI. But I got an empty document for xen.cfg. There’s no [global] section at the top, or a default= line.
This leaves me with the Grub2 option.
I guess I should try that option. I would need to modify this line:

GRUB_DISABLE_SUBMENU=false

and Add this line:

GRUB_SAVEDEFAULT=true

Then run

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

And reboot.
I will backup my computer prior to doing this and see if it will work.

#4

nevermind, sorry

#5

You can also uninstall kernel-latest via dnf in dom0. Just make sure you keep kernel installed.
You can always check via e.g. dnf list | grep kernel what kernels you have installed.

There’s also kernel-510 for the 5.10 LTS line, if you prefer that. If you need to install a specific kernel version, I’m not sure whether there’s an easy way for that.

At boot you can select installed kernels from GRUB as previously mentioned already.

#6

I’ve been losing sound the past few days too. I wasn’t sure why though. I have to switch the output device back and forth a few times until it works, but it’s only good for the open vm or until I put the computer in suspend.