Latitude E7470 - Laptop display become black screen when HDMI cable is plugged in

[KevinSee]

Issue:

Whenever I plug in the HDMI cable into the laptop, the laptop built-in screen will become black screen. However the external monitor is working fine. I tried mirror mode and standard mode (extended display) and both will result in black screen for the built-in laptop screen.

 

I need to restart the laptop in order to get the built-in screen to be working again - without plugging in the HDMI cable. Once I plug in the HDMI cable, then it will become black screen again.

 

Even I have unplugged the HDMI cable from the laptop, the black screen on the built-in monitor remains.

 

Here is the link to the EFI: https://github.com/skevin83/Hackintosh-Dell-E7470

 

The EFI folder size exceeded the maximum allowed to be uploaded here. Thus I put it in GitHub.

 

Specification

Dell Latitude E7470 Laptop

INTEL CORE I5-6300U

12GB DDR4 RAM 2133MHZ

256GB SSD STORAGE M.2

INTEL HD GRAPHICS 520

14" INCH HD 1366x768

 

I performed a fresh installation of Catalina then upgrade to Big Sur.

 

Thanks.

IORegistryExplorerResult.zip

[KevinSee]

After the laptop fell into sleep mode and wake up again. Now both external monitor and laptop screen are working fine. 

 

That's interesting.

[Jake Lo]

Yes I posted this some 4-5 years ago on my guide here since Sierra, not sure it affects El Capitan or not. Been too long.

You could try EDID to fix it