How to downgrade to Linux kernel 4.15.x on ubuntu?

I'm using ubuntu 18.04 which runs on linux kernel 5.4.0. And i wish to install and use Linux kernel 4.15.x cause that works better on my system. Can anyone please guide me how to do that.

1 Answer

You need to remove the 5.4 HWE kernel (backported from Ubuntu 20.04 LTS) and install GA 4.15 back with which Ubuntu 18.04 LTS was shipped.
Use commands below:

sudo apt-get autoremove --purge 'linux-image-5.4.0-*-generic' 'linux-image-unsigned-5.4.0-*-generic' 'linux-modules-5.4.0-*-generic' 'linux-hwe-5.4-headers-5.4.0-*' linux-generic-hwe-18.04 linux-image-generic-hwe-18.04 linux-headers-generic-hwe-18.04
# allow removal of running 5.4 kernel in the ncurses blue prompt - answer 'No'
sudo apt-get install --install-recommends linux-generic
sudo apt-get install --install-recommends linux-image-generic linux-headers-generic

If you also need to disable HWE for Xorg/X11, then use below command:

sudo apt-get install xserver-xorg
sudo apt-get autoremove --purge 'xserver-xorg*hwe*18.04'

If you have Nvidia card then run

ubuntu-drivers install

before reboot.

Details: