Hi ghaverla, nice to meet you.

I hate for your troubles. But in the last few months, I've been thru EXACTLY (mostly) what you're going thru, and I'd like to try to help. What makes my experience 'mostly' is that I had compile problems on 3 computers, and I had AMD Catalyst problems on a 4th computer. Hopefully, you can combine my lessons learned on one computer and find joy. I'm gonna try to take your posts one at a time, top to bottom.

Letting the tasks finish and upload and get no new work was the right thing...kudos. That should have been enough, and I know the projects appreciated it.

Your HD 5450 is barely in the usable range of compatible GPUs. Might consider an upgrade soon. In my BOINCsperience, NVIDIA is much easier to work with. BTW, I love the term BOINC-fu. Maybe your room needs some BOINC-shui.

MESA is designed to work only with non-proprietary drivers, in your case, Radeon and AmdGpu (not Pro) in the repos. xorg-radeon is AMD's non-proprietary driver for its older GPUs, xorg-amdgpu is AMD's non-proprietary driver for its newer GPUs. I don't know where the dividing line between old and new is.

I have seen boinc-client show up in my home folder before. I ignored it and just kept going. BTW, not in Devuan, in MX.

Using the Distro's Version, rather than compiling, is the best way to go if you can. I think your upgrade to an upgrade to an upgrade may have left some things not right, systemically. Multiple unsuccessful re-installs of an Application is a sign of this.

I hate that noone replied to you for so long. I saw your post 2 weeks ago, but was not in the right mind to reply. Today, I am.

I love to move and upgrade hardware. Hope you had fun.

The boinc-client starts on boot-up by default. Users must suspend/resume projects/tasks manually to their likin'.

Glad you found that 'compile client only' flag. I had to visit 3 or so different Web Pages to get all the instructions I needed. Then I still had to wait for the compiler to tell me something was missing.

I extracted and compiled in my Home Folder. I think this made write permissions less of a problem.

It sounds to me like you're trying to mix files from the Distro's BOINC installation with the Compiled BOINC installation. This is a booboo. They are not compatible. The Distro Version uses Symbolic Links throughout the tree. The Compiled Version is completely self-contained in its own folder. It compiles completely and solely in the same folder to which it was extracted. It places nothing anywhere else in the tree, not in /etc, not in /var. The Distro Version's symbolic links will interact with any files anywhere in the tree that have 'boinc' in their name, including those in the Compiled Version's folder. You must choose one version or the other, and completely remove all files of the one you don't choose (backup boinc-client first). Catfish is your friend.

Your last post indicates that you chose the Compiled Version and it's working, except for GPU. Congratulations. Still uninstall the Distro Version and remove all rogue files. Apt-get autoremove, GtkOrphan, and BleachBit are good friends too.

OPINION: After all the things you did, undid, and rearranged, a fresh install of DevJessie upgraded to Ascii may be worth considering. If you wish, see my reply to leloft for my take on that.

Now you're back to the original problem in your original post, getting your GPUs to run OpenCL tasks.

I don't think you need any 32-bit libs, other than the deps pulled in by BOINC and the Video/OpenCL Drivers.

MY TAKE: Uninstall/remove all things proprietary AMD/Catalyst/fglrx and use the xorg-radeon driver only. If it won't uninstall, claiming that some files have been changed, just remove /etc/X11/xorg.conf and /etc/modprobe.d/blacklist-fglrx. A reboot should take you back to the xorg-radeon driver.

You're experienced with MESA so install whatever you like from it's collection. I installed: glx-provider-mesa, opencl, va, utils & extra, vdpau, and vulkan. There was plenty of MESA stuff already installed by the OS install, but these pkgs looked necessary/handy to me, and I don't think too much MESA will do any harm.

FAIR: This is my first attempt at MESA, it having been made necessary by smelly AMD OpenCL support in Stretch/Ascii/xUbuntu16.04/DevJessie. It was fine in DebJessie. So, my skillset in this area is highly undeveloped.

IMPORTANT NOTE!!!: As well as my AMD GPUs run BOINC tasks now, this Radeon/MESA combination is not powerful enough to run tasks and desktop graphics/video well simultaneously. Some 'points & clicks' take a few seconds to respond. Since the computer in question is our Home Theater PC, and Graphics/Video are primary, my solution was to 'exclude_gpu_0' in cc_config.xml, as that is the GPU that runs the TV/Monitor. The other two AMD GPUs run tasks continuously without consequence.

These are my thoughts, hope they help.
Post your progress, regardless of my influence. I'm interested.

Gary

It's nine months later and this problem is not solved.
There is no longer any 'preview' button that I can see.
There is also no box to tick for 'keep me logged in'.
I just spent about 3 hours composing my first post in reply to a person who had not had a single reply to his long thread of posts in 2 weeks, not from a dev or admin or anyone. I think myself uniquely qualified to help him so I tried, only to be logged out automatically and have my reply deleted. I'll have to cool my jets before I can try again to help the guy.
Please put a tip in some obvious place about autologout and composing, copying, and pasting from a text editor, so new folks will know. This is an unreasonable barrier to folks trying to help folks. I've never seen it on any other forum.

On a positive note, what Devuan is doing is rare and valuable, and I'm committed to it. I will work with the circumstances that prevail and help to find a better solution if I can. To start, I'd like to suggest a 'Read This First Before Posting' section at the very top of the Index. Many forums have them and I find them very helpful and useful.