New Windows 10 Insider Preview Fast+Skip Build 18922 (20H1) - June 19 Insider

CountMike said:

Just as I suspected, Mixed up BOOT partitions. I would disable Disk 7 and reinstall windows on disk 6, they should look identical except the letter C would be on disk you actually boot fro at that time. You may also want to use Samsung Magician to allocate some space for Over provisioning, it allegedly helps with SSD longevity, specially if close to full. Some data is actually swapped to that partition so all cells get same wear and tear when written to.

Thank you.
There is no way (in the UEFI BIOS) to disable Socket m2_1. So I guess I will have to physically remove the card.

Leaves me with a question about getting the system to dual boot, after clean installing Insider again, and then re-installing the NVMe card with 1903. Will Windows see there are two systems and add both to its boot manager ???

Thanks for your comments about Over-provisioning. That can be done after I have everything else set up correctly.

CountMike said:

It could be done from MSCONFIG.exe but I prefer using EasyBCD EasyBCD - NeoSmart Technologies to make a BOOT menu on primary disk

Thanks again. Yes, I know, and have used EasyBCD for years. But it slipped my mind when I was thinking about dual booting. At 86, I reckon I'm allowed a few senior moments.

To customize the boot menu’s settings from within Windows.

1. Control Panel
2. System
3. Advanced System Setting
4. System Properties
5. Advanced tab
6. Startup & Recovery.
7. Choose the default boot operating system
8. Select how long you want to wait until it boots
9. OK

Thanks to all who have responded to my request for advice.

One last question before I head for bed.

Are there any downsides with the setup as it is, no System partition, no Recovery partition?
Or is there something that might come back to bite me later?

I'm not very concerned about the lack of a recovery partition, I prefer to use an image from Macrium Reflect if a need to restore/reset/recover arises.
But I just don't know what effect having no System partition may have.
I haven't seen any problems since finishing the clean install. But I'm just an end user who likes to be on the cutting edge. I am usually able to fix problems with my machines. But I have no coding/programming knowledge.