reproduce (this is a W=1 build):
        # https://github.com/frank-w/BPI-R2-4.14/commit/b4f36e791b05f368a838ea83b520a8d881bc6b63
        git remote add frank-w-bpi-r2-4.14 https://github.com/frank-w/BPI-R2-4.14
        git fetch --no-tags frank-w-bpi-r2-4.14 7.2-rc
        git checkout b4f36e791b05f368a838ea83b520a8d881bc6b63

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash