SparcV

I've been having problem getting Catalina to work correctly, I have a screen corruption issue, it starts about halfway through the boot up. I tried lots of settings in both Clover and OpenCore in an attempt to get it working. This is a i5-4570S with iGPU on the latest bios version A20 from 2019. The system works perfectly in both Windows and Ubuntu Linux. Is there some setting I'm missing? I've attempted to use the 9020 non-AIO guides to get it work but none resolve this issue. However when using an external display attached to the HDMI port it works fine, just the external display.