Windows 10 Update broke my Windows 8 Install

I have two SSDs one with Windows 10 and one with windows 8.1.

I booted into the windows 10 install(press Del to invoke BIOS and then selected windows 10 to boot) I told it to start updates and walked away as it takes awhile. When I got back it was at a BSOD which I didn't think much of just thought it crashed. Restarted comp and told it to boot to windows 10 SSD again, it finished the update and started windows 10 just fine. When I went to switch back to my 8.1 SSD the problems started I keep getting a 0xc000021a BSOD.

I have tried the following to fix this error

WinRE: Startup repair PC Refresh Bootrec /fixMBR Bootrec /fixBoot Bootrec /rebuildBCD

SFC /ScanNow says there is a repair pending so I tried a bootable USB Drive with windows 8.1 on it and tried this command

SFC /SCANNOW /OFFBOOTDIR=X:\ /OFFWINDIR=D:\Windows
It then told me there was corrupt files but it was unable to fix them.

Once when I ran the WinRE auto repair it said to look at this file for more info

C:\Windows\System32\LogFiles\Srt\SrtTrail.txt says

Root cause found

Bugcheck c000021a. Parameters = 0xffffc00058000e30, 0xffffffffc0000428, 0xffffc0005da7d7e0, 0x0. Boot critical file is corrupt.

Repair action: File repair Result: Failed. Error code = 0x2 Time taken = 1578 ms

The 0xc000021a seems to be related to a bad Winlogin.exe or Csrss.exe file so I tried copying those from a known windows 8.1 install but it said I need permissions from trusted installed to copy them and I kinda gave up at this point.

Has anyone else run into this problem when installing windows 10 or does anyone have any other ideas on how to fix this problem before I reinstall windows 8 on this SSD.

Thanks Chris