Ubuntu - GPU - AMD GPU - Troubleshooting - System will not boot

Problem

Booting the system freeze immediately. It may show:

/dev/nvme0n1p2:  clean...
...recovering journal

but does not continue.

NOTE: There is a missing kernel module.

sudo add-apt-respository ppa:kisak/kisak-mesa
sudo apt update
sudo apt upgrade

NOTE: This will install the latest stable MESA-driver.

sudo vi /etc/apt/preferences.d/kisak-pin-2000

and populate with:

Package: *
Pin: release o=LP-PPA-kisak-kisak-mesa
Pin-Priority: 2000

and update again:

sudo apt update
sudo apt upgrade

mkdir /home/peter/amdgpu
cd /home/peter/amdgpu
git clone https://git.kernel.org/pub/scm/linux//kernel/git/firmware/linux-firmware.git

NOTE: The /home/peter/amdgpu directory here is just a temporary directory.

The git command will download the firmware into a sub-directory named linux-firmware within the /home/peter/amdgpu directory.

If git command does not work, download the newest tar.gz file manually from https://git.kernel.org/pub/scm/linux//kernel/git/firmware/linux-firmware.git

mkdir bak
sudo cp -R /lib/firmware/amdgpu bak

NOTE: This backup can be used, just in case this is needed.

sudo cp linux-firmware/amdgpu/* /lib/firmware/amdgpu

NOTE: This will copy the amdgpu drivers from /home/peter/amdgpu/linux-firmware directory, to /lib/firmware/amdgpu.

sudo update-initramfs -c -k $(uname -r)

sudo shutdown -r now

Remove the temporary directories that were created for this fix.

sudo rm -Rf /home/peter/amdgpu