As someone who recently discovered MySQL-5.1 on my WD Arm based NAS. I thank you for a story of MariaDB actually being on a NAS (or at least used to be).
Can I get some more information as to how MariaDB got there? Where was it installed from?
MariaDB has ended 5.5 releases and there is 1 more 10.1 release to go, however all new releases are still coming every 3 months or so.
What does 'stopped working' mean? Is it failing to start? What exact error is being encounter? Which MariaDB are you after?
Which Intel Atom model is it (/proc/cpuinfo)?
Is there a qemu command line that can execute the QNAP TS459 Pro+ CPU and firmware image?
The NAS is a QNAP TS-459 Pro+ MariaDB is installed as part of the firmware, with no way that I have found to be able to update it. The version that is used is 5.5.57.
The problem I am encountering now, is when trying to log into the DB via PHPMyAdmin, I receive the following...
mysqli_real_connect(): (HY000/2002): No such file or directory
I use Joomla for our intranet here, and trying to bring up out intranet results in the following...
Error displaying the error page: Application Instantiation Error: Could not connect to MySQL.
The processor in the TS-459 Pro+ is a 1.8Ghz Dual Core Atom CPU
Not entirely sure what you are asking on that final line. If you are asking if I can manually update the firmware, then yes, but it is via the UI not command line.
I just downgraded the firmware to an older version, the one they told me had the best chance of working, and am waiting for the unit to finish rebooting to see if that worked, I just hate rolling back the firmware due to loosing the security fixes that the new firmware versions add.
I have no idea why they do not update their firmware to use a more recent version of MariaDB. I have asked them, but while answering most of my questions, they have ignored that one 
If I could figure out a way to manually install a newer version, without conflicting with the non functional version they have installed, I would go that route, but I don't know how to install software on this thing, other than through their app center, and it doesn't contain MariaDB, MySql, or any other flavor of SQL unfortunately.
I appreciate your help, but my guess is that until they decide to fix their reliance on a no longer supported version of the software, I am just going to have to be stuck.
Thanks,
-Larry
The first 5.5 release (5.5.20) was in Feb 2012, the last (5.5.68) — in May 2020. 5.5.57 was release in Jul 2017.
Every major release is supported for 5 years, but in 2017 we've extended support for 5.5 until 2020.
But even the extended period has to end eventually.
Latest MariaDB major release is 10.5, supported till 2025 — https://mariadb.org/about/#maintenance-policy
QNAP has to upgade MariaDB at least once in five years otherwise, indeed, the version will go out of support according to the published schedule.
It seems that you can install MariaDB in a docker container, at least google found some suggestions to do that.
And you can tell QNAP support that Synology, apparently, offers packages for MariaDB 10.3 
I appreciate your response, and it makes perfect sense. I will reach out to QNAP again, but I doubt it will be of much help 
They still will not answer me as to why they have not updated to a current version. I may have to look into replacing the QNAP, considering the level of support they have been providing on this issue
Again, thank you for the response!!
-Larry
For QNAP, or whoever wants to build a QNAP application:
https://wiki.qnap.com/wiki/QPKG_Development_Guidelines seams reasonably easy to follow. There will be a little manual build options with installing MariaDB into arch dependent location and non-architecture locations but not too much. These will be cmake -DINSTALL_Xxxx=location options (per https://github.com/MariaDB/server/blob/10.5/cmake/install_layout.cmake#L41-L61).
For getting a built binary of the compatible architecture use:
-DCMAKE_C_COMPILER=(path to c compiler) -DCMAKE_CXX_COMPILER=(path to c++ compiler) -DCMAKE_C_FLAGS=-m(cpu/arch)=(lowest CPU architecture) -DCMAKE_CXX_FLAGS=-m(cpu/arch)=(lowest CPU architecture)
Try to stick to native compilation. Cross compilation is possible but it can be a little fiddly.
MariaDB-10.5 has some performance improvements on Arm and work is continuing.
On versions, good news - 5.5 to 10.5 upgrades are possible:
read notes:
https://mariadb.com/kb/en/upgrading-between-major-mariadb-versions/
doing a 5.5 package (or firmware) thats includes a config option innodb_fast_shutdown=0 before a 10.5 package would be ideal.
If you need some advice - ask on https://mariadb.zulipchat.com , we may not have a QNAP on hand, however I'm sure we can work out some problems or work out the questions to ask of QNAP support/community developers.
Thank you.
I have passed this information on to QNAP, but I doubt they will do anything. They claim that they are not doing updates to my unit due to hardware limitations, but I think that they just don't want to spend their time on their older products
I may take a look at this myself, and see if it is something I can do personally, and sideload onto the NAS
I really appreciate all of your help!