IORegistryClone VS ProperTree

First of all make sure you have a backup of your current EFI then try some patching. Then grab a copy of IOReg and open it. Search for iGPU entry and locate entry (eg. AppleIntelFramebuffer@0 in my case) with a child “display0” it controls the physical display. Select that entry (eg. AppleIntelFramebuffer@0) and on the right panel locate connector type. Then check if it’s set to “00 08 00 00” or not. (This is the connector type for HDMI). If not then. Leave it as it is (in case of laptops it is mostly 02000000). Then open your config.plist in propertree and head to DeviceProperties -> Add -> PciRoot(0x0)/Pci(0x2,0x0). Then add these entries here (Don’t touch anything already present there just add these) “framebuffer-patch-enable = 01000000”, “framebuffer-conX-enable = 01000000” and “framebuffer-conX-type = 00080000” [IMPORTANT: make sure X in conX is the number you’ll find in the ending of AppleIntelFramebuffer@ which you located previously and make sure it has a child “display0” this is important (in my case=0)] and save the config.plist and reboot. Your HDMI port should be working now. Not 100% sure about it but it works most of the time.

IORegistryClone - https://github.com/khronokernel/IORegistryClone

IORegistryClone - Utility to browse IO registry with a GUI interface, it can be useful for patching features such as CPU power management, USB mapping, etc

Do you have IORegistryExplorer ?

Open the config in ProperTree (https://github.com/corpnewt/ProperTree) and do a clean snapshot (CMD-SHIFT-R). This will put all of the kexts in the right order.

Open your config.plist using ProperTree.

NO. Prebuilts are a bad way to start. They are not updated and aren't configured to your specific needs. Make your own EFI and also don't use OCAT, use ProperTree which can do OC specific things like OC (clean) snapshots.

ProperTree

Try looking into a program called ProperTree. Has a GUI implementation to easily edit https://github.com/corpnewt/ProperTree

Used the Ryzen and Threadripper(17h and 19h) OpenCore Install Guide for with OpenCore v0.8.7 in combination with OpenCore Auxillary Tools, Sanity Checker & ProperTree.

Use propertree. It is hands down, the best IMO. https://github.com/corpnewt/ProperTree

You need to mount your EFI partition (find a tool online or use command line). In it you should find "EFI/OC/config.plist". Open the file with Propertree or another plist editor and make the changes.

If anything, keep .contentFlavour files removed and try updating your config.plist using ProperTree or some other plist editor which just makes it easier to read. Sorry I couldn't be of much help but its the best I've got right now haha.