I upgraded from 18.04 to 20.04. LTS and the update-manager crashed with "Oh no. Something has gone wrong" in the process of upgrading. Through the terminal, I seemingly completed the upgrade with the steps from here and can boot into the system fine now.
I found out that the kernel has not been updated and I'm still running on 4.15
$ uname -a
Linux ubuntu 4.15.0-96-generic #97-Ubuntu SMP Wed Apr 1 03:25:46 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
I tried to install the 5.4 kernel with
apt install linux-headers-5.4.0-26-generic linux-image-5.4.0-26-generic
which worked fine and I restarted the system. From there, I noticed the screen was in low resolution and lshw -c video
did no longer use the radeon driver.
On 4.15, it uses the correct driver and all seems well:
root@ubuntu:/home/oliver# lshw -c video
*-display
description: VGA compatible controller
product: Hawaii PRO [Radeon R9 290/390]
vendor: Advanced Micro Devices, Inc. [AMD/ATI]
physical id: 0
bus info: pci@0000:01:00.0
version: 80
width: 64 bits
clock: 33MHz
capabilities: pm pciexpress msi vga_controller bus_master cap_list rom
configuration: driver=radeon latency=0
resources: irq:141 memory:c0000000-cfffffff memory:d0000000-d07fffff ioport:e000(size=256) memory:dfe00000-dfe3ffff memory:c0000-dffff
How can I update to the newer kernel while retaining radeon graphics driver support?
The issue was implicitly resolved with the upgrade to 20.04.1, which introduced a newer kernel version. This will likely not help anyone stuck in that state, but on the other hand this likely will no longer occur with 20.04.01 out.