[Fw_Os_Forum] "Virtual serial port" provided by AMT SOL not visible in UEFI loader?

[Brett Stahlman]

I have enabled (in HP Z 240 firmware options) Intel AMT (Active
Management Technology) and the SOL (Serial over Lan) capability it
provides. Since my system has no actual serial port, I assumed SOL
would provide a good way to capture serial debug output emitted by my
loader. Unfortunately, LocateProtocol returns EFI_NOT_FOUND for
EFI_SERIAL_IO_PROTOCOL. After boot, the OS (Windows 7 in this case)
sees the virtual serial port as COM3. Why doesn't the UEFI firmware
see it? Surely there is a way to access this port from UEFI
firmware... If any one knows of any other relatively easy ways to
capture debug loader output from systems with no actual serial port
(e.g., using one of the USB stream protocols?), I'd be eager to hear
about that as well...

Thanks,
Brett S.