(1) "
Disk 0 is now the selected disk.
DISKPART> list part
Partition ### Type Size Offset
------------- ---------------- ------- -------
Partition 1 System 300 MB 1024 KB <<<EFI
Partition 2 Reserved 128 MB 301 MB
Partition 3 Primary 129 GB 429 MB
Partition 4 Primary 329 GB 129 GB <<<Your D: drive
Partition 5 Recovery 900 MB 459 GB
Partition 6 Recovery 16 GB 460 GB
Windows Boot Manager
identifier {bootmgr}
device partition=\Device\HarddiskVolume4 <-- Should it be replaced with EFI
allocated disk Volume1?
"
I would expect it should say HarddiskVolume1 just as you suspect. That is your EFI partition going by its type in the Detail Disk you showed...
Partition 1
Type : c12a7328-f81f-11d2-ba4b-00a0c93ec93b <<<That's correct for EFI
Let's see a Detail Part on partition 4 (which is your D:drive)...
DiskPart
Select Disk 0
Select Part 4
Detail Part
Exit
DIR D:\EFI\MICROSOFT\BOOT\BOOTMGFW.EFI /a <<<And is the file there?
(a) It should normally be a basic data partition: ebd0a0a2-b9e5-4433-87c0-68b6b72699c7
(b) And normally that folder & file shouldn't be on it. It should be on EFI.
(c) Are you booting to the Windows Boot Manager in BIOS Setup?
It does look suspicious to me. I've seen a case where booting directly to a drive caused the HarddiskVolume number to be different from my expectation. But even if your BIOS does boot directly to disk 0, I'd still expect to see HarddiskVolume1. So, I'm really confused to see ...4.
(2) "
Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
* Volume 2 SYSTEM FAT32 Partition 300 MB Healthy System <-- Under Label, should it be
stated as "EFI" instead of "System"?
"
No, the Label can be anything. It needs to say "System" under "Info" just as it does. And it should be FAT32 just as it is. Usually it is 100 MB, but your 300 is OK. I believe some types of drives may even require the larger size.
(3) Your ReagentC /Info indicates partition 6 is the Recovery partition...
Windows RE location: \?\GLOBALROOT\device\harddisk0\partition6\Recovery\WindowsRE
Judging from its size of 16 GB, it is a factory reset partition. So, a Reset would return the computer to its factory condition whatever that OS may be. If the computer came with Win 8.1, for instance, you'll end up back there. That could get messed up by doing an upgrade.
Have you upgraded the OS since purchase of the computer? Or did it come with 1909?