reproduce (this is a W=1 build):
        # https://github.com/frank-w/BPI-R2-4.14/commit/d35953f4687e0059a657274066a7dfbf1b6d4173
        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 pr/188
        git checkout d35953f4687e0059a657274066a7dfbf1b6d4173

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash