On Fri, 23 Oct 2020 16:42:53 +0200
Edward Bartolo via Dng <dng@???> wrote:

> Dear All,
>
> Lately, on an HP Probook 4540s, while booting Devuan Boewulf the
> screen becomes completely unreabled with unsynchronized lines of
> pixels.

Which kernel?
Was it recently upgraded?
Which video drivers are your using?
What is your display configuration?

My only suggestion is to ask if you can reboot on an older kernel and
achieve a working solution.

Also check if your video hardware is supported by the video drivers
your system is attempting to load. (Hint check /var/log/dmesg.'n'
and /var/log.Xorg.1.log).

IME, sometime after generally upgrading to Beowulf, the
default(startup) video drivers went askew. I first noticed this when
I attempted installations of Devuan beowulf onto 'clean' hardware.
With one system I had to go back to Jessie to be able to do a basic
server install.

Since my problem was on a AMD FX motherboard with AMD video card under
the "Radeon" driver, the problem may not be HP related, but rather
something to do with code for AMD.

In other, probably useless information, you can now upgrade kernel up to
5.8 through backports (sudo apt search linux-image-5), but I doublt if
that will fix your problem.