Well, I can assure you that I didn't change anything in my .config when I built the 4.19.133 and .137 kernels; I always copy my latest/current /boot/configXXX file to ./.config before running `make xconfig` for a new kernel, and then do a visual diff afterwards.

I could have run into the same issue after installing my 5.7.14 kernel build, but fortunately I ran into what actually seems like a plausible explanation researching a trivial build failure: don't call `finish_cpu()` when offlining a core. I've added an answer with sources to the stackexchange topic referenced in my OP.

I think I finally managed through a combination of changing the settings in that file and in /etc/default/locale. It worked, but it's not exactly the kind of (novice) users of an otherwise fancy and frankly quite nice looking desktop to have to jump through.

I even installed an admittedly basic version of the Gnome desktop to be able to follow instructions I found related to the gdm display manager (hoping that would ease my pains) but no such luck (and I quickly remembered why I loathe that DE so much).

Full disclosure: I'd have put that user under KDE but for some reason it starts to a black screen, I guess because the imported $HOME was configured to use a KDE Plasma4 desktop (and possibly because Devuan's KDE version isn't exactly the latest). I'd have reinstalled Plasma4 if someone still provided packages for it; it still works just fine and KF5 applications integrate seamlessly with it.

I suppose the power LED doesn't go off (if you have one)?

As far as I can tell there's a regression that was introduced in the 4.19 kernel sometime after 4.19.118 (aka 4.19.0-9 in Debian speak). See https://unix.stackexchange.com/question … 19-0-9-ker

It always makes me chuckle when people suggest that any use of free software (esp. under the GPL) isn't entirely at your own risk... It's very easy on Ubuntu too to break something with an illconceived package from a PPA. In fact, using multiple package sources in a design that's already subject to dependency nightmares (split packages with individual, versioned dependencies) is already a recipe for disaster in itself. Been there, done that... (heck, I almost lost my entire install because I thought I could simply back out of experimenting with the official systemd package for Trusty, without using ZFS snapshots as a safety net).

Was it your intention to link to the generic Debian wiki landing page (on which I didn't see a DontBreakDebian section)?

Do Debian and/or Devuan have a similar site/service in place? Upgrading to just about any newer distro would presumably rob me of my preferred (minimalistic) KDE Plasma4 (sic, Four) DE so I'd be very tempted to get that up and running myself and evidently I'd prefer to be able to use an external build service for that.

EDIT: there must be a matching Ubuntu version for any given Devuan distribution version, that has the crucial libraries should be in the same place, right? If so, a Launchpad PPA with custom packages based on the Devuan packaging metadata (the `debian` subdir) ought not be too risky?