Okay, so I used Xcode to:
1. remove MatchOS and MatchBuild fields
2. remove old "4 displays" patch which has problem
3. verify both new "4 displays" & "port 0x7 to hdmi" patches ok
4. save config.plist
Then rebooted with "-f" boot arg, then rebuilt cache, then rebooted again.
Sorry to tell but I still get black screen. Framebuffer@3 is still not appearing... see my 5.zip below
Note: I also tried to patch it to mac14,2 instead of 17,1 but same result so I reverted back to original configuration
Tried to capture below dmesg. Does it help?
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sudo dmesg | grep IGPU
[IGPU] Will fallback to host-side scheduling if graphics firmware fails to load
[IGPU] Scheduler Tail Coalescing Enabled.
[IGPU] Scheduler Tail Coalescing Enabled.
[IGPU] Chose to use graphics firmware based on platform
[IGPU] *****************************************************************************
[IGPU] Failed to initialize graphics firmware. Falling back to host-side scheduling
[IGPU] Scheduler interface revision = 1: Default EL Scheduler
[IGPU] *****************************************************************************
[IGPU] Graphics accelerator is using scheduler interface revision 1: Default EL Scheduler
[IGPU] Scheduler: Multiple channel indexes per command streamer
[IGPU] Scheduler: Process CSB using HWS.
[IGPU] Scheduler: PM notify enabled
[IGPU] Graphics Address: PPGTT, Separate Address Space
[IGPU] MultiForceWake Enabled: Using 3D Driver
[IGPU] Scheduler Throttle Cap = 100ms.
***