Windows 8.1 to Windows 7

[heathercat123]

NTDEV made a video on downgrading Windows 8.1 to Windows 7. He successfully gets to the login screen by running Windows 8.1's first stage setup in "no reboot" mode (/noreboot) and in Windows 7 compatibility mode and swapping the install.wim in C:$WINDOWS.~BT\sources by Windows 7's. However, after the Windows 8.1 setup sets up the wrong operating system (which is what we want!) and eventurally gets to the login screen, trying to log in threw The RPC server is unavailable This issue is most definitely fixable, searching it on Youtube even tells you how to fix it on Windows 11! Also, according to a comment on the video, the same issue appears when downgrading from Windows 8.1 to 8.0, but not 8.0 to 7.

Edit: You can find fixes for Windows 7 by using Google or any other search engine (I personally use DuckDuckGo, but Google is more popular) and specifically search for Windows 7.
Edit 2: In the video, he sets compatibility mode. However, in my experience, you can only keep Windows settings and apps with it.
Edit 3: Stage 2 setup crashes at 83%
Edit 4: Trying to use Windows 7 after the crash will make it crash at Starting services. Interestingly enough, it's booting from C:$WINDOWS.~BT\NewOS.
Edit 5: I am going to try again, but with the Windows 8.0 installer. If that doesn't work, then I'll try to downgrade to Windows 8.0 first.
Edit 6: Trying to use Windows 8's installer opened a r3dfox window with the text 'Restart your PC to continue the installation'
Edit 7: Deleting the Windows Setup boot entry fixed it, it's now going through stage 1!
Edit 8: It's stuck at 14%
Edit 9: I tried using NTDEV's trick with the Windows 8.1 installer and the Windows 8 install.wim and it got past stage 2!
Edit 10: I get The RPC server is unavailable and it rebooted a few seconds after. It's troubleshooting time!
Edit 11: I tried to restart from the login screen, but There are no power options available
Edit 12: People's solutions are something along the words of replacing the entire SYSTEM hive. Maybe using a stock Windows 8 hive may help? I'll try booting without automatic restart at failure first.
Edit 13: I booted into Safe Mode with sethc bug and I discovered that the RPC service was running. I also found out about a guy who said to rename Locator.exe in SYSTEM32, might be worth trying
Edit 14: Replacing the SYSTEM hive causes a bootloop, which then starts Automatic Repair, which fails.
Edit 15: Running net user in cmd using sethc bug also throws the RPC error. The downgrade may just not be possible after all.
Edit 16: I tried attaching a kernel debugger via ethernet, but internet connection as a whole doesn't work without RPC. I'll try replicating my downgrade in a virtual machine so I can use a COM port.
Edit 17: I managed to attach a debugger via COM port to Windows 8.1. I will now downgrade.
Edit 18: Stage 2 setup crashes at 83%. I guess I got a non-working Windows 8 ISO? (I used x86 ISOs for the VM, x64 for real hardware). I guess I'll try making an x64 VM then.
Edit 19: I now have an x64 VM attached to the debugger! Time to downgrade!
Edit 20: Stage 2 setup crashed again, even with the x64 ISOs