I upgraded my motherboard/process/RAM from an HP Z420 to an HP Z440. Since the upgrade my RX 6600M will not display until Windows loads. I had to use an older card with a VGA port to see the POST and configure BIOS. With the BIOS set to Legacy mode I get no display from the RX 6600M at all. With BIOS set to UEFI Only, it will display in Windows. I have tried HDMI and all Display Ports. No change. My monitor is an older Acer LCD with HDMI, DVI and VGA. I'm running Windows 10 Pro. It seems the nVidia had a similar issue with their newer cards and had to put out a UEFI BIOS update for their video cards so they would display via Display Port (not HDMI) during system startup. Could this be a similar issue with the Radeon?
