coreboot

Hi
We have developed a custom board using tgl up3 processor. Uptil now we were building slimbootloader for checking all interfaces. We were successful with all peripherals except audio codec which is connected via soundwire interface and that support is not present in slimbootloader. Hence we decided to shift to coreboot. The issue we are facing is that in slimbootloader we stitch the bios bin with the IFWI (Gbe Me etc) and create a FULL image that is flashed on board. However, with coreboot only the bios is generated and we dont have any rom.layout for our custom board. I havent yet tried Flashing the bios image generated with coreboot as it is. As it may fail without the IFWI image. Could you help us out in our initial setup. Any help would be greatly appreciated.