BSOD - Inaccessible Boot Device

Ok, I think I'm in a big doodoo now, really big.
The rig is: Windows 10 1803 on an crucial ssd mx250 drive (ahcpi in bios), the latest dec 11 cumulative update was ready to be dowloaded, but has not been installed.
Everything was fine, until I foolishly decided to follow crucial's executive storage drive utility suggestion to disable 8dot3name compatibility for my OS volume (don't judge, I believed crucial's ad about performance benefits without doing googling first). So i did it with fsutil 8dot3name set 1, then I decided to reboot and got the BSOD.
Automatic repair failed, got thrown into winpe.
*First thing I tried, is to revert the 8dot3name state for the os volume from winPE: fsutil 8dot3name querry volume-blabla, fstutil 8tot3name set volume-blablab 0 - got the same BSOD
* Tried using dism on the OS volume: dism /image:H\ /cleanup-image /restore health - got error 2: unable to access the image.
Sfc, as far as I understand, is imposibble to target to a specific drive in winpe, so no luck with it. Chkdsk - runs fine, but doesn't fix the bsod.
* Tried a restore point, and succesfully restored to a two days prior - got the same BSOD.
* Tried Solved: INACCESSIBLE BOOT DEVICE in Windows 10 - Driver Easy in case there WERE bad packages. Got the same error 2 at the Dism /Image:H:\ /Get-Packages stage.
* I tried resetting bios - same BSOD.My system has been functioning perfectly well from the first win10 release, survived all redstone updates with flying colours, been successfully cloned to a new ssd, and in the end it was me who killed it with my own stupidity.

It just gets better.
Attachment 217250

I also have an additional empty 500mb partition, but can't see how it could be the problem,it has been there for a long time since the RS upgrade bug happened, and didn't bother me.
Attachment 217276

Won't let me fix the boot record. Also, during the previous reload into winpe, bootrec /rebuildbcd would find the H partition with OS, but still wouldn't do it's thing for the readons I don't remember already.
Attachment 217282

Managed to run DISM on H partition - no effect.
Attachment 217290
Tried to remove 2 packages potentially related to spectre fix which may cause my issue. Got an error 0x800f082f.
Attachment 217292
/rebuildbcd flag still doens't want to see the H volume during it's search. No identified windows installations.

Some options are:
1) backup all important files to another drive > clean install
2) perform a reset save files equivalent ( reinstall drivers and applications)
3) command prompt troubleshooting steps

zbook said:

Some options are:
1) backup all important files to another drive > clean install
2) perform a reset save files equivalent ( reinstall drivers and applications)
3) command prompt troubleshooting steps

The 1-2 are cheap cop outs - I'm gonna slay that b. :) Besides, I just feel it in my guts that I have a correlation - not causation situation here. Most likely, 8.3 stuff is not the culprit, it's the opportunistic spectre patch(es) that suddenly woke up and screwed up my boot! I just need to circumvent the0x800f082f issues and delete them, I think i've found the solution, I just don't understand the second part of the post very well (tired!). Which patch (in my case) i need to donwload and unpack. Windows 10 INACCESSIBLE_BOOT_DEVICE BSOD - Windows - Linus Tech Tips

ALso, could you post the 3) steps, I'm so VERY tired and overloaded right now, cant google more than I have to. Thanks.

The reset save files equivalent if successful should be the quickest method to get you backup and running.

The backup files then clean install is the best option as you fix many problems and start fresh.

The command prompt commands are all trial and error.

Code:

1) bcdedit /enum
2) bcdedit | find "osdevice"
(note the partition drive letter displayed in the result as this drive letter will be used in many of the later commands)

Code:

3) diskpart
list disk
list volume
select disk 0
detail disk
list partition
select partition 1
detail partition
select partition 2
detail partition
select partition 3
detail partition
select partition 4
detail partition
select partition 5
detail partition
select disk 1
detail disk
list partition
select partition 1
detail partition
select partition 2
detail partition
select partition 3
detail partition
select partition 4
detail partition
select disk 2
detail disk
list partition
select partition 1
detail partition
select partition 2
detail partition
select partition 3
detail partition
select partition 4
detail partition
select disk 3
detail disk
list partition
select partition 1
detail partition
select partition 2
detail partition
select partition 3
detail partition
select partition 4
detail partition
select disk 4
detail disk
list partition
select disk 5
detail disk
list partition
select disk 6
detail disk
list partition
exit
(post an image of the results into the thread)

Code:

4) chkdsk /r /v T:
(replace the drive letter T: with the partition drive letter displayed in the result for step 2)
(This may take many hours and typically displays ETA)
(reboot to run the command)
(post an image of the result into the thread)
(reboot after the command completes to check the boot)
(reopen command prompt for the next step)

Code:

5) dism /image:T:\ /cleanup-image /revertpendingactions
(change the drive letter T: to the drive letter displayed in the result for step #2)
(reboot after the command completes)
(reopen command prompt to run the next command)

Code:

6) dism /Image:T:\ /Get-Packages
(change the drive letter T: to the drive letter displayed in the results of step #2)
(Run the following command on the last installed package:
example: dism.exe /image:T:\ /remove-package /packagename:Package_for_KB4014329~31bf3856ad364e35~amd64~~10.0.1.0
(change the drive letter T: to the partition drive letter displayed in step #2)
(Reboot)
(perform this command on multiple KB as needed to go back in time to before there were boot problems)

Code:

7) sfc /scannow /offbootdir=T:\ /offwindir=T:\windows
(change the drive letters T: to the drive letter displayed in result for step #2)
(This command may take a while to run)
(post an image of the results into the thread)
(reboot to check the boot)
(open command prompt for the next step)

Code:

8) bootrec /fixmbr
9) bootrec /fixboot
10) bootrec /scanos
11) bootrec /rebuildbcd
(post an image of the result into the thread)
(reboot after the command completes to check the boot)

Ok, I made a stupid u-turn on my path to removing the spectre patches. I now know that i have my win 10 installed (since it was upgraded from win 7) wil a legacy bios-mbr scheme! BIOS/MBR-based hard drive partitions | Microsoft Docs
So when I selected my os drive and detailed it, I saw 3 partitions: sys res, os one, and a hidden one in the end (as I now know: a recovry), I deleted both 500mb partitions because i though they were duplicated/corrupted! Genious!
Got a black and white Windows failed to start. 0xc000000f screen. So, I created an active 500mb partition again, formatted it to ntfs, labled it and assigned a letter K, then did bcdboot f:\windows /s K: /f BIOS. Then successfully managed to run bootrec /rebuildbcd and rebooted. My mobo supports both bios and uefi, so I probably should've chosen "ALL". Anyway, I think I fixed it back to the BSOD screen. Haven't bothered with recovery partition, I'll create it later. Have I done everything right?


Also, funny thing: via usb 3.0 (only uefi avail) in winpe i can do bootrec /fixmbr successfully without access denied, but with usb 2.0 and choosing legacy WinPE boot - I can't? Do you know why it is so?

Alsoalso: here is a log screenshot when I get 0x800f082f error trying to delete the package with dism. Does it mean anything?
Attachment 217343

Please post images of the results of the commands in post #8.

Repeat sections 1 - 3 as necessary to post images of the partitions, volumes, disks, osdevice, etc.