I would do what awokd said with the multiple vga adapters option, I would also consider using grub as a payload and/or selecting Coreboot Execute Option ROM's/VGA Option ROM's with the appropriate YABEL options/restrictions for security (more secure than SeaBIOS method)
Youness he is using a KGPE-D16 which has no ME/PSP, so that issue can be ruled out.
Tips: Reducing the serial log level to one or two will drastically speed the boot time.
The OpenBMC beta is now available if you wish to have an open source BMC and use the ASMB4 module.