Ubuntu with kernel 5.8 and nVidia legacy drivers

Problem:

• Cannot install drivers from nVidia website on Ubuntu with kernel >= 5.8 (nVidia has dropped support for legacy drivers!)

Solution:

• Download patched nVidia installer for your card and kernel
• Install packages for building kernel module

$ sudo apt install build-esssential gcc make libc6-dev

• Create /etc/modprobe.d/blacklist-nvidia.conf with following content:

blacklist rivafb
blacklist rivatv
blacklist nvidiafb
blacklist nouveau

• Update initramfs

$ update-initramfs -u

• Reboot and log in to console (ALT+F3)

$ sudo reboot

• Stop X server

$ sudo service gdm stop # replace gdm with your manager if different

• Run installer

$ chmod +x ./*.run
$ sudo https://nvidia.if-not-true-then-false.com/NVIDIA-Linux-x86_64-XXX.XXX-patched-kernel-5.8.run

• Install additional packages

$ sudo apt install vdpauinfo libva-glx2 libva-drm2

• Reboot and enjoy
• Remember that you need to install nvidia module after every kernel update

For newer kernels (up to 5.11) see If-not-true-then-false website.