I am having the same issue, loop reboot after fresh windows 10 install under open core, but that also happened to me with an old imac 27", and I am trying to use the same method to debug it:
It is due to some drivers most likely, either from windows updates or from bootcamp.
Here are a couple of hint to help you and may be we can share progress:
my recommendation for the windows 10 install:
1) Install without internet being connected (to prevent windows 10 picking up updates)
2) To allow recovery and troubleshooting:
2.1) Enable the F8 recovery option at boot (not enabled by default)
From cmd admin windows:
bcdedit /set {default} bootmenupolicy legacy
2.2) Enable Restore point on boot drive (not enabled by default) and create restore point right after having created your basic logins and etc in windows to get back to a bootable testable windows 10 *without non install drivers*
3) Put windows updates updates on pause
4) Disable installation of Driver updates by Windows
Settings -> System -> about-> Advanced System Settings -> Hardware Tab -> Device Installation Settings -> Pick No
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If you want to install the full bootcamp: the different version of AppleHFS drivers (AppleHFS.sys) I have tested so far disable windows restore capability and for some people also create bootloop, so best to disable it until you troubleshooted . If you want to use a reg file:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AppleHFS]
"Type"=dword:00000002
"ErrorControl"=dword:00000001
"Start"=dword:00000004
"Group"="File System"
"AutorunsDisabled"=dword:00000000
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