[coreboot] I7-7600U(KabyLake) with Vxworks

Hi

I'd like to make coreboot.rom for I7-7600U(KabyLake) to boot Vxwork with coreboot.
Payload will be Vxworks 7.

I've succeed to boot by using ApolloLake (Up Squared).
At that time, tried Tianocore(EFI/Vxworks) and ELF Boot(Vxworks) and succeed.
because I used coreboot V4.12 and it's supported for UP squared.
I've got bios.bin and descriptor.bin from AMI BIOS by using ifdtool.
and then added cpu_microcode_blob.bin, fspm.bin and fsps.bin and so on.

can see message like below.
1. Boolblock stage
2. Rom Stage
3. Postcar Stage
4. Ram Stage
5. Vxworks Prompt.

but When I make coreboot.rom for KabyLake, I can't see any message by Hiperterminal.
I just can use intel / kblrvp... and added descriptor.bin and me.bin and so on.
but.... not success yet...

Have you ever made this chip? Do you have any kindly documentation? or 
I 'd like to hear exactly informations for more details.
Please help me.