- Does the system refuse to boot at all when a modern UEFI GPU is installed?
If there is a monitor plugged in, yes. It won't pass POST. However you can boot without a monitor plugged in and the card should be available for VT-d passthrough.
- Are any errors logged in the PCH event log?
I'll have to check. Where do you view the PCH event log? I don't have IPMI working yet. There are a LOT of errors logged to the onboard serial console.
- When a UEFI GPU is installed is there any activity on Serial-over-LAN (SOL), IPMI, AMT, ME, SPS or other OOB management?
I'll have to check once I get IPMI working.
- What about the system's RS232 serial or debug header?
Yes, there is a repeating error on the debug header when you try to boot with a UEFI graphics card and a monitor plugged in.
The errors look
similar to this one (but not exactly the same):
ERROR: Type:2; Severity:80; Class:3; Subclass: D; Operation: D
From my short research on UEFI errors, they seem to be vendor specific (e.g. referring to a specific module in the UEFI firmware) so it's only through observation that I personally believe it is the UEFI video stack causing issues.
- Has anyone tried installing an both a older card that's known to work and a modern UEFI card at the same time (in an attempt to boot using the old card and let the OS initialize the newer card).
I have only one card, so I cannot test this. From the behaviour I have witnessed, as long as there is no monitor plugged into the UEFI card, it will boot.
In my testing I have found:
- BIOS flashed card: works
- UEFI flashed card: works only if no monitor is connected (so there is no VGA output from UEFI or the main OS)
Since I got VGA working on my board, I have updated the firmware to the latest version (2014_WW45.1_F03C3A07.zip) which is much newer than the original firmware that shipped on my board:
Version 2.14.1219. Copyright (C) 2011 American Megatrends, Inc.
BIOS Date: 03/02/2012 13:08:57 Ver: F03_3A07
The newer firmware even has explicit options in setup to boot in UEFI mode, something I was never able to get working on the original firmware. I'm going to try and flash my GTX 650 back to UEFI firmware and see if it's possible to boot with VGA with the latest Quanta firmware from 2014.