MacOS partition not shown in Bootcamp Control Panel

Is there any way to get the Bootcamp Control Panel (in Windows, while running on a Mac via Bootcamp) to somehow “rescan” for all the available startup volumes?

A few months ago, I installed an SSD in my 2012 Mac Mini, with the idea that it would replace the existing internally mounted spinning HD. In addition, I purchased the necessary hardware from OWC that enables me to have both drives installed inside the Mini, so that is the state of things now. As I was running MacOS 10.14 Mojave at the time, both Mac partitions are APFS formatted, and as such are not normally visible to Windows via Bootcamp, except for the Bootcamp Control Panel.

I was able to transfer everything from the old spinner to the new SSD, and thanks to Winclone 8, was able to clone the old spinner’s Bootcamped Windows partition to the new SSD. Long story short, all four partitions are bootable and run properly. I can select from all four partitions in the MacOS’s System Preferences > Startup Disk panel, AND I am able to select from all four partitions when I start up holding the Option/Alt key. The only issue that is problematic, and I admit is more of an annoyance than anything else, is that in those times when I am running Windows, having previously selected the SSD’s Windows partition in the MacOS’s System Preferences as Startup Drive, I cannot perform the corresponding preference change back to the SSD’s MacOS partition from the Bootcamp Control Panel. The MacOS on the spinner shows up there, but not the one from the SSD - and it would be nice if I could somehow get it to do this.

I thought that it might somehow fix itself if I simply disconnected the spinner HD inside the Mini, but this is a really finicky job that I’d rather avoid if at all possible. Has anyone else experienced something similar and come up with a solution for the “missing MacOS startup partition” issue I’ve described?

After months of procrastination, I removed the System folder on my older, spinning, internatl hard drive. Now the only bootable Mac Partition on my Mini is the one on my internal SSD.

I did this in the hopes that it would somehow “force” a rescan for actual, bootable partitions in both the MacOS and in Windows (still Win10, v. 1809), but there is no change.

Under Windows, the Bootcamp Control Panel shows only the old, spinner’s Mac Partition, even though it is no longer bootable. If I hold down the Option key during start-up, I still see all four partitions (two MacOS: one on the SSD, the other on the spinner; and two Windows, each on each drive), even though the old MacOS partition no longer has a valid System Folder and is therefore not bootable. If I do select the old partition, just to see, I get a “not available” symbol (circle with diagonal line through it) and it proceeds no further.

Back on the SSD’s Windows partition, I reinstalled the Bootcamp components from a USB Thumbdrive in the hopes that it might trigger a rescan of available startup partitions in the Bootcamp Control Panel, but there is no change - the only available MacOS partition shown there is the now no-longer functional one on the older, spinning internal drive.

It seems to me that pre-OSX, you could “unbless” a bootable partition by simply removing the “Finder” or “Desktop” file from the System folder, and the computer would no longer recognize that partition as bootable. I couldn’t discover a way to do anything like this with Mojave v. 10.14.6.

Does anyone know some other method I could try to get Windows operating systems to “see” and recognize as bootable the MacOS partition on my SSD? Yes, I can still access the Startup Disk Preferences under the MacOS and select the SSD’s Mac partition as the preferred Startup, but it would be nice if I could get the Bootcamp Control Panel in Windows to see and recognize the Mac partition on my SSD.

Any suggestions?