upl.coreboot.shimlayer

Helper Code for coreboot to load payload that comply Universal Payload Interface

Build Requirements

• make (GNU Make 4.2.1)
• clang (clang version 10.0.0-4ubuntu1)
• nasm (NASM version 2.15.05)
• llvm-ar (LLVM version 10.0.0)

How to build Shimlayer

Create a new directory , and using the below command

cd <workspace>  
./CorebootShimBuild.sh  

ShimLayer.elf is generated in <workspace>/Build folder.

How to replace ShimLayer and UniversalPayload

Please refer to https://github.com/coreboot/coreboot to build coreboot.
After building coreboot, you can use coreboot tool cbfstool to replace ShimLayer and UniversalPayload to coreboot.rom .
Copy ShimLayer.elf and the target UniversalPayload.elf to <coreboot_workspace>/build.
Use the below command

cd <coreboot_workspace>/build
./cbfstool coreboot.rom remove -r COREBOOT -n fallback/payload
./cbfstool coreboot.rom add-payload -r COREBOOT -n fallback/payload -f ShimLayer.elf
./cbfstool coreboot.rom remove -r COREBOOT -n img/UniversalPayload
./cbfstool coreboot.rom add-flat-binary -r COREBOOT -n img/UniversalPayload -f UniversalPayload.elf -l 0x200000 -e 0x100 -c lzma

Then the coreboot.rom has been replaced to your ShimLayer.elf and the target UniversalPayload.elf now.