SOLVED BlackScreen after validating root dmg

[alenxba]

At now graphics working 50/50.

I have partically video accel in os (smoother mouse movements), but windows collapsing are laggy.
In game fps normal and no lags.
And i have colors bug, like a sepia:



This effect with this parameters:

• AAPL,ig-platform-id : 00001259
• device-id : 12590000

Without device-id save result.

Used SMBIOS - iMac18,2 and iMac18,3
Yes, i tried iMac18,1, with it no video input.

OS seeing Monitor EDID and showing it info correctly.

IOReg:
https://drive.google.com/file/d/187KpsO7ruF0DPfPjBWiBLm-PYw8BUaaK/view?usp=sharing

 

[alenxba]

Fixed.

• SMBIOS: iMac18,1
• AAPL,ig-platform-id: 00001259
• Boot args: igfxagdc=0

 

[EliteMacx86]

Fixed.

• SMBIOS: iMac18,1
• AAPL,ig-platform-id: 00001259
• Boot args: igfxagdc=0

This was the ig-platform-id you were being told to inject. igfxagdc=0+EDID and the SMBIOS was the key. Glad its solved.