seems that somehow one instance of variable substitution doesn’t happen, and it ends up creating a directory named UefiPayloadPkg$(BUILD_ARCH) instead of UefiPayloadPkgX64
@mateidibu nice work! I’m working on getting a nix-shell for building coreboot but I’ve been told to go the flake route as we have mixed results in testing the nix-shell. Could you suggest changes to this PR?