Thank you for giving a hint to the out-of-date firmware and its
implications.
I wanted to update my firmware using fwupdmgr and the firmware binary
files provided by Lenovo. Unfortunately the firmware can only be flashed
when the system boots via UEFI, but my computer won't boot in UEFI mode,
I can confirm that downgrading intel-microcode to version
"3.20191115.1ubuntu3" resolves the issue. I've marked the package as "on
hold" for now.
Here's my "lscpu" output that I forgot in my initial report:
Architecture:x86_64
CPU op-mode(s): 32-bit, 64-bit
Public bug reported:
Installed Ubuntu 20.04 from USB disk using the first Ubuntu 20.04
installation image released end of April. The system installs and boots
fine. Then, I run a system update via `apt update && apt upgrade` with
updates to Ubuntu 20.04.1. intel-microcode is updated on this
