Comet Lake UHD 9B41 spoofed as 9B3E: internal 4K eDP detected but validateDisplayMode returns 0xe00002c2 on FB0

[aalexfmc]

Hardware:

• Dell XPS 13 7390
• CPU: Intel Core i7-10510U, Comet Lake-U
• iGPU real PCI ID: 8086:9b41
• OpenCore: 1.0.7
• macOS: Sonoma 14.8.3
• SMBIOS: MacBookPro16,3
• Internal panel: AUO 3840x2160 eDP 4K

Current IGPU injection:

• AAPL,ig-platform-id = 00009B3E
• device-id = 9B3E0000

Observed behavior:

• External display works with Metal acceleration.
• Internal panel shows verbose boot, then goes black when accelerated graphics initializes.
• With no external monitor connected, boot remains/stalls around verbose/graphics transition.
• Connecting external display later allows macOS to finish and show login externally.
• With -igfxvesa, internal panel works, but there is no acceleration.
• With real device-id 9B410000, internal panel works without acceleration; external is black.

Linux facts:

• Internal connector: eDP-1
• Encoder/port: DDI A / PHY A
• AUX: AUX CH A
• Native mode: 3840x2160 @ 60.002250 Hz
• Pixel clock: 533.300 MHz
• Panel EDID: AUO model 10283
• DPCD main bytes: 14 00 c4 c1 00 00 01 c0 02 00 00 00 00 0b 00
• eDP DPCD bytes: 04 92 a5 00 00
• Linux i915 uses 4 lanes, HBR2/max rate 540000, 24 bpp
• No eDP training failures in Linux

macOS debug findings:

• Internal panel appears under AppleIntelFramebuffer@0.
• FB0 has AAPL,boot-display, built-in, port-number 0, AUO EDID present.
• FB0 DPCD is readable:
  • Display port config ver is 1.4
  • Maximum link rate is 0x14
  • Maximum lanes is 4
  • Display status is 1
• FB0 does not get active IOFBCurrentPixelCount / active IOFBConfig in accelerated state.
• Logs repeatedly show:
  • IGFB:: validateDisplayMode:2214 return 0xe00002c2
• External FB1 modesets and flips normally.

Tests already tried:

• DPCD max link rate fix and manual dpcd-max-link-rate 0x14: no effect.
• framebuffer-con0-type 00080000: no effect.
• igfxonln=1 and igfxonlnfbs=0: no effect.
• -igfxblr, -igfxblt: no effect.
• complete-modeset: no effect.
• enable-cdclk-frequency-fix: no effect.
• con0 flags/pipe/busid/linkwidth variants: no effect.
• DVMT stolenmem/fbmem only: no effect.
• EDID same override: no effect.
• custom 4K30 EDID: caused boot failure/reboot.
• enable-max-pixel-clock-override 675 MHz: caused reboot loop.
• enable-max-pixel-clock-override 550 MHz: stuck at verbose/graphics transition.
• igfxagdc=0: caused reboot loop.
• -igfxmpc: caused reboot loop.
• 07009B3E platform: external works, internal not useful/disappears.
• 0000A53E + A53E0000: external works, internal black.

Question:
Given that FB0/eDP is detected, DPCD and EDID are readable, Linux trains the link correctly, but AppleIntelCFLGraphicsFramebuffer repeatedly rejects validateDisplayMode with 0xe00002c2 before internal modeset, what is the most appropriate next diagnostic step or WEG property to test?

Attached diagnostics:

• config-current.plist
• IORegistry from stable accelerated external boot
• framebuffers dump
• displays dump
• WEG/Lilu framebuffer logs
• Linux eDP/i915 diagnostics summary

Additional note: I have a sanitized diagnostics package with config-current.plist, framebuffer logs, display dumps and IORegistry available if needed.