How to update kernel to specific version

Question

I would like to upgrade to specific kernel version (5.4.0-81-generic) from following current state on different servers. I would like to use apt package manger to update kernel.

Ubuntu 18.04.3 LTS  4.15.0-55-generic
Ubuntu 18.04 LTS    4.15.0-51-generic
Ubuntu 18.04 LTS    4.15.0-20-generic
Ubuntu 18.04 LTS    4.15.0-106-generic
Ubuntu 18.04 LTS    4.15.0-133-generic
Ubuntu 18.04 LTS    4.15.0-140-generic
Ubuntu 18.04 LTS    4.15.0-107-generic
Ubuntu 18.04.4 LTS  5.4.0-74-generic
Ubuntu 18.04.4 LTS  5.4.0-77-generic

ls /boot
config-4.15.0-76-generic  grub                          initrd.img-5.4.0-70-generic   System.map-5.4.0-70-generic  vmlinuz-5.4.0-70-generic
config-5.4.0-70-generic   initrd.img-4.15.0-76-generic  System.map-4.15.0-76-generic  vmlinuz-4.15.0-76-generic

uname -r
5.4.0-70-generic

I get following 2 images when try to search for kernel version, which one to use.

apt-cache search linux-image | grep 5.4.0-81-generic
linux-image-5.4.0-81-generic - Signed kernel image generic
linux-image-unsigned-5.4.0-81-generic - Linux kernel image for version 5.4.0 on 64 bit x86 SMP

Now, how to safely, gracefully update only the kernel version -

apt-get upgrade linux-image-5.4.0-81-generic

Solution

Warning: doing things below is dangerous if you care about system security. Proceed only if you are sure what do you want to achieve.

So you have to remove meta-package (it usually depends on the latest kernel, nowadays it is 5.4.0-86 in this HWE stack) by

sudo apt-get update
sudo apt-get remove linux-image-generic-hwe-18.04
sudo apt-get autoremove

and then install fixed version by

sudo apt-get install linux-image-5.4.0-81-generic

But please again note that latest kernel is safer, it may have many CVEs fixed. Check changelog for details.

So to get all latest upgrades back you have to execute the following commands:

sudo apt-get update
sudo apt-get install --install-recommends linux-generic-hwe-18.04  
sudo apt-get dist-upgrade # to get all latest dependencies

and then reboot to use all latest software including the kernel.

---

More stuff to read:

• man apt locally or online, man apt-get locally or online
• https://wiki.ubuntu.com/Kernel/LTSEnablementStack#Ubuntu_18.04_LTS_-_Bionic_Beaver
• https://help.ubuntu.com/18.04/serverguide/package-management.html

Comments

[N0rbert]

Does this answer your question? How do I restore the default repositories? It is already in official repositories. To keep your system secure you have to install security upgrades (not just only kernel).

[unknown]

My question is more on how to install specific kernel version using apt package manager.

[N0rbert]

Please add output of ls /boot and uname -r to the question.

[unknown]

added output of ls /boot and uname -r

[user535733]

You question should clearly explain exactly why you want a specific older kernel. It can be done, but it's a corner case. The explanation will help dissuade new users (the main frequenters of this site) from erroneously downgrading their kernels.

[unknown]

Could you please let me know where did you find ` linux-image-generic-hwe-18.04 ` and what it is and why it is to be removed.

[unknown]

I was looking at wiki.debian.org/HowToUpgradeKernel which didn't say anything to be removed. what's the significance of removing meta-package, please let me know.

[N0rbert]

Packages like linux-image-5.4.0-81-generic are dynamic dependencies of linux-image-generic-hwe-18.04 . Current is 5.4.0-86 .

[unknown]

Isn't my current kernel is '5.4.0-70-generic' as per uname -r command output and how is it related to removing met-package 'linux-image-generic-hwe-18.04' will remove my old package.

[N0rbert]

You have to understand dpkg/APT internals more carefully. Please read the relevant docs. Then execute apt-cache rdepends linux-image-5.4.0-70-generic to understand the relations between it and linux-image-generic-hwe-18.04 package. You have to learn tools and system before doing strange things, IMHO.

[Promise Chukwudum]

Thank you for the answer. I followed the steps and successfully installed 5.10 and 5.13.19 kernels on 18.04.6 LTS. I used mainline to install these kernels.