reproduce (this is a W=1 build):
        # https://github.com/tobetter/linux/commit/5fa32be6d7ce558be554b60a740b8906fcc0e648
        git remote add tobetter https://github.com/tobetter/linux
        git fetch --no-tags tobetter odroid-6.6.y
        git checkout 5fa32be6d7ce558be554b60a740b8906fcc0e648
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=um SUBARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=um SUBARCH=i386 SHELL=/bin/bash drivers/char/