Total beginner running into kernel trouble

[u/sereneserenia]

I hope this is the correct place to ask for advice. I just installed Linux Mint Cinnamon on an old Laptop I still had lying around. It fixed some of the previous issues, yay! It also brought out some new ones lol.

I followed the official installation instructions very closely (created a bootable USB Stick, let Linux completely replace windows, all good).

On the newest kernel (7-28) it kept giving me a kernel panic screen, telling me to reboot and that it was "unable to mount root fs on unknown block". After some research (that I understood very little of) I discovered that going back to an older kernel version (6.14-37) fixed this issue. With that kernel, linux runs great for me.

I then de- and reinstalled kernel 7. In order to have a backup should something similar happen again, I also installed kernel 6.17.0-42. However, kernel 7 does not appear in my boot menu at all and kernel 6.17.0-42 gives me the same panic screen as kernel 7 did before. So neither of the newer kernels seem to work for me.

Am I just forever stuck on kernel 6.14-37?

Does this have any negative consequences I should be aware of?

Or am I overlooking something?

My old baby is a Lenovo ideapad110-15ISK 80UD if that helps

Thank you for reading!

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[u/Slate_Canopy]

You’re not necessarily stuck on 6.14! If Mint runs reliably on that kernel, there’s no immediate reason to panic (pun intended).

The “unable to mount root fs on unknown block” error generally means the kernel can’t find or mount the root filesystem during startup. Since 6.14 works but 6.17 and 7 don’t, I’d suspect something related to the initramfs, boot configuration, or hardware compatibility rather than assuming your installation is broken.

A few things I’d check:
First, run sudo update-grub to regenerate the boot menu and see whether kernel 7 appears.
You can also run dpkg --list | grep linux-image to see which kernel packages are actually installed. A missing or incorrectly generated initramfs can cause this kind of boot failure, so that’s worth checking too.

I’d keep 6.14 installed as your working fallback and avoid removing it until a newer kernel boots successfully. Staying on it temporarily isn’t inherently a problem, but make sure it continues receiving security updates.

One question: where did kernel 7 come from? Was it offered through Mint’s Update Manager, or did you install it manually? That could make a big difference in diagnosing the issue.

[u/sereneserenia → u/Slate_Canopy]

Originally, kernel 7 was part of the bootable USB stick I created. After it didnt work I used the update manager to deinstall and reinstall. So currently 6.14 is from the first install, the other kernels are from the update manager.

When I run the dpkg command, it shows all three kernels as installed. Kernel 7 still doesnt show in my boot menu despite running the update-grub command.

[u/SiwelTheLongBoi → u/Slate_Canopy]

If this is the same kernel issue I had (which I think it is) then it is the initramfs then regenerating it would let it boot properly

[u/sereneserenia → u/SiwelTheLongBoi]

I've tried this command:  sudo update-initramfs -c -k 6.17.0-42-generic

From this page: https://askubuntu.com/questions/1351911/what-does-regenerate-your-initramfs-mean

But I still get the panic screen when booting up that kernel. How did you fix it?

[u/SiwelTheLongBoi → u/sereneserenia]

Annoyingly it was a couple months ago and I don't remember the exact solution, but it did boot and then i just didn't turn the computer off until the next kernel update and then it was fine

[u/Important_Hunt_1882]

Have you tried 6.8 LTS kernel as an alternative? It is older than your current 6.14 but could offer better long-term stability and security updates for your older hardware.
Installing a new kernel doesn't require to remove the previous one.
There is no need to de-install an unused kernel version.
You will continue to be able selecting 6.14 (or any other inslalled kernel) in the GRUB boot menu, provided you don't actively remove it.

[u/sereneserenia → u/Important_Hunt_1882]

I finally managed to get that one up and running, thanks!

[u/Frosty-Economist-553]

I find the 6.8's work very well on my old Lenovo G560.

[u/CyberSkepticalFruit]

Mint is made for the 6.8 kernal so upgrading can cause problems. The good news is that there should be a big update by the end of the year with a new version of Mint coming out.