When booting via/in UEFI mode, my display connected to a discrete graphics card via HDMI is blank, until Windows starts to load. Why is my hdmi-connected display not showing during UEFI boot?
a) I have a DP-connected display to the same card and it has a signal during UEFI boot.
b) In the UEFI GOP setup, I have my discrete card/driver indicated and set to HDMI.
I have the exact same issue, but through HDMI, and it is monitor-specific. My Dell U2213 does display the UEFI... as does at least 2 (both I have) TV with HDMI-in. My dell se2717h display does not- it displays a message that I should set my monitor to X resolution, which happens to be the current, native resolution of the monitor. I've been trying for some time (a year!!!) to figure out where, exactly, the fault lies... and my warranties are running or have run out. So I have to haul another display in to change any uefi/bios settings.
Could be the source, the Vega 11 part of my Ryzen 5 2400G
could be the mobo, a gigabyte x370 gaming 5 board (with no VGA out!!!),
could be the monitor is somehow faulty (even though it works perfectly in every other way)
could be driver or chipset software...
It is not the cable- happens with several, incl., a pricy high-bandwidth cable (not Monster)
I spent a while sending support requests to AMD, Gigabyte, and Dell and got no useful communication- for the most part I was shunted off to the "support" of the community, and when I tried opening tickets I was essentially told they have no idea and it is probably due to [insert either other vendor or software here]. Nobody had any useful response. I kinda gave up but am still occasionally looking for info that would help. havent found any.