Hello
@pastrychef,
I've been running this Golden Build of yours since 2018 with a Radeon RX580. For a couple years now it's been happily on 10.15.7 but I thought I'd try to upgrade it to Big Sur or Monterey now.
It seems that Catalina was the last MacOS where TonyMac made a Unibeast, and is now recommending OpenCore, which at first glance I do not understand. I thought the smartest thing to do would be to first upgrade to your newest OpenCore EFI folder and see if the machine boots at all, and if it does then work my way through upgrading the OS.
I made a CCC backup and a backup of my current EFI folder, then put in your latest OpenCore EFI folder, put in my MAC address, MLB, Serial, and UUID, and booted. I get a black screen with three icons, a Windows disk icon (I have a hard drive with Windows 10 also in the computer), an EFI external disk icon (my CCC backup), and "Reset NVRAM." But my Catalina partitions, which are APFS as you'd expect, and on an M.2 drive, and not FileVault encrypted, are nowhere to be found. Strangely, the Windows 10 drive doesn't even boot correctly anymore, and selecting the "EFI" disk icon takes me to the Clover EFI on the CCC backup, which no longer responds to keypresses and also doesn't show my Catalina partitions - I'm sure OpenCore is injecting a lot more stuff into memory than Clover ever did and Windows 10 and Clover don't like running after it is loaded.
I tried searching for an answer and there seems to be a secure boot option in config.plist that breaks Catalina if it's not disabled. I disabled it and nothing changed. I also changed the Mac model from iMacPro1,1 in your config.plist to iMac18,1 which is what I've been running as the last few years, and that also changed nothing.
What have I done wrong here? It would be inconvenient but not the end of the world to do a clean install. If I've missed something simple I'd like to try that first, though. But since the machine is one of my daily drivers perhaps I should be thinking about just going to the last version of Big Sur instead of Monterey as I'm sure there are many bugs for Apple to fix. OpenCore is supposed to let you install OS updates with less fuss, right?