Coreboot have just a support for PCIe OXPCIe952 card and it's complete deprecated and old board. the price of uart boards compatible with coreboot, have a complete expensive price and all is used.

All these problems, that makes hard to use coreboot with Serial console.

Serial console use can help computer without compatibility of USB EMbedded Controller Console.

Serial console is complete important for both old and new boards ports and fixes.

Please if coreboot can support new cheap common serial console PCIe boards in future, it's can be great for future ports and fixes in olders boards include in the use for best 64BIT coreboot table support in the most boards.