Windows 10 to 8.1

[heathercat123]

NTDEV managed to "upgrade" Windows 10 to Windows 8.1, but left no instructions on how. However, we have two videos to work with: Video 1 Video 2

[heathercat123]

In Video 1, he sets compatibility mode to Windows 8 on installprep.exe and launches it. He also disables WinRE so he can see what's preventing Windows from booting. After that, from WinPE, in HKLM\SYSTEM\ControlSet001\Services\Wof, he sets Start, SupportedFeatures and Type to 4. He repeats this with WindowsTrustedRT, although he doesn't set SupportedFeatures.

[heathercat123]

In Video 2, he attaches a debugger, which we don't need for the guide. He also plays around with Notepad's file picker with absolutely no indication of what he's doing. Maybe he's trying to see if the files which are causing the error actually exist? Or maybe it's their modification date?

In the registry, he sets to 4:

• FileCrypt
• WdBoot

He renames (in system32):

• Coml2.dll

Another possible way of doing this may be to see which drivers in that folder have a version number higher than Windows 8.1's (9600) or have a file time of 2015+ and then delete them or use the registry trick, the only exception being coml2 which is outside of the drivers subfolder.

And I think that's it! Now I just have to test it!
Edit: It may be easier to disable the services BEFORE the downgrade