reproduce (this is a W=1 build):
        # https://github.com/frank-w/BPI-R2-4.14/commit/b323ef91cc6a2146182ab5616b9f648847025bd4
        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 6.18-rc
        git checkout b323ef91cc6a2146182ab5616b9f648847025bd4

        # 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 drivers/net/phy/