Step 3 - Build the coreboot toolchain

Please note that this can take a significant amount of time. Use CPUS= to specify number of make jobs to run in parallel.

This will list toolchain options and supported architectures:

$ make help_toolchain

Here are some examples:

$ make crossgcc-i386 CPUS=$(nproc)       # build i386 toolchain
$ make crossgcc-aarch64 CPUS=$(nproc)    # build Aarch64 toolchain
$ make crossgcc-riscv CPUS=$(nproc)      # build RISC-V toolchain

Note that the i386 toolchain is currently used for all x86 platforms, including x86_64.

Also note that you can possibly use your system toolchain, but the results are not reproducible, and may have issues, so this is not recommended. See step 5 to use your system toolchain.