I fixed the issue in a similar manner to what
hahnweiler suggested, though there are some necessary added steps.
1) I replaced the dumpsd.sys and sdbus.sys contained in the Windows/system32/Drivers directory, with the copies contained here:
https://files.theminixforum.com/shared/drivers/Z83-4-Driver-Fix_SD_card_cannot_be_seen.zip
2) I replaced the sdstor.sys file contained in that same directory, with the copies contained in the attachment found here:
https://forum.chuwi.com/thread-6634-1-1.html (The attachment in the first post, "
SD drivers by nandinhus.zip")
(Note, there are TWO copies of that file within the ZIP. I used the copy found in the "SD_CLASS_STORAGE" sub-directory. )
3) I made all three files read-only (we'll see how well that goes) and restarted. Problem solved.
The tricky part was getting around the TrustedInstaller protection that prevented me from renaming, replacing or deleting the files contained in the Drivers directory. I had to change the advanced security settings of each of the three files, first changing "ownership" of the file from TrustedInstaller to "Administrators", then editing the permission rights deleting TrustedInstaller and giving full access rights to Users. (There's probably better guides online as to how to remove TrustedInstaller protection, but it's not that difficult. In any case, always copy backups of files before messing with these things.)
Anyways, once I changed those settings for all three of those files in the Drivers directory, I was able to rename/move/delete them, and replace them with the "new" system files (from steps 1 and 2.)
Note --- I tried installing these same files by running the INFs included, and by browsing/updating the drivers manually via Device Manager, and neither method worked, among many other attempts. This is the only success I've had. Cheers to MINIX and
hahnweiler.