Thanks Casey,
I updated to OC 0.6.1 so it contains USBInjectALL 0.7.6 from your OC update guide and files.
Think I will try the following and see what happens:
1. Go into my current OC config.plist and select the model to be iMac 20,2 (since I have the AMD 5700 graphics card).
2. Doing that seems to change the Serial Number, Board Serial Number, and System UUID. It also adds PlatformVRAM information, BID, Firmware Features, Firmware Features Mask.
3. Do model lookup and check coverage so that everything passes muster.
Move that EFI folder to my Boot Flash Drive and see if it will boot (with Ethernet unplugged)
If that boots, sign out iCloud and move the EFI folder to my System Boot partition and see if the system will boot and is stable. Plug ethernet back in and log back in to iCloud. [After making a backup of course
]
Thanks
Rand