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[Solved] 7400 with HDMI output 720 res only ...no 1080p

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I have 7400 model with custom EFI built for 7400 and weirdly I can't establish fullhd res (1080p) on the external monitor, it is going blank. Is fine when 720 is set instead.

I've swapped DP connectors to HDMI in the framebuffer, have full accel. but 720 res is working only without problem unfortunately ...no 1080p.

Any advice on where to look? EFI folder with config, essential kexts and amls attached.




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Thanks Jake Lo.


CPU model is i7-8665U.


Actually switching to 15,2 instead didn't make any difference but pointed me to check the framebuffer settings once again. After changing AAPL,ig-platform-id and recheck the fb's conectors 1&2 types ...the problem has been resolved.

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Sure thing.


Before I had both AAPL,ig-platform-id and device-id set to Iris 655 but with a mistake as below




This is incorrect. AAPL,ig-platform-id should be 0900A53E. Anyway, after fiddling with settings again I thought to use UHD 620 values this time.




also, framebuffer-conX was not set correctly followed old settings below




con1-alldata was set with 00080000, which is HDMI. Compared with others, I've decided to split alldata values and start counting conX from 1 instead of 0.


Correct settings are:

AAPL, ig-platform-id == 00009B3E

device-id == 9B3E0000


with framebuffer as:



Everything functioning well afterwards. I did test it with SMBIOS for MBP15,4 and  MBP15,2. I do believe with AAPL, ig-platform-id: 0900A53E and device-id: A53E0000 should work as well, followed https://elitemacx86.com/threads/intel-uhd-graphics-620-whiskey-lake-on-laptop-clover-opencore.455 . So, in my case, framebuffer-conX key values were set incorrectly.


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