>> I would boot from an installation USB / CD (preferably the one you set
>> the
>> machine up from) and go into Rescue Mode, and see whether the hardware
>> still
>> continues behaving the same way.
>
> I just did that on the latest Devuan Beowulf Live distro (kernel
> 4.19.0-14), and... no flickering!

Booting back on the internal disk... No flickering.
I just don't get it. Would it be hardware/cable-related in the end?
*sighs*

Bernard (Beer) Rosset
https://rosset.net/