CFLAGS="-march=armv6 -mfpu=vfp -mfloat-abi=softfp"
CFLAGS="-march=armv6 -mfpu=vfp -mfloat-abi=hard"
CFLAGS="-O3 -march=armv6zk -mfpu=vfp -mfloat-abi=hard -mcpu=arm1176jzf-s -mtune=arm1176jzf-s"
production here "-O2 -march=armv6zk -mfpu=vfp -mfloat-abi=hard -marm -mcpu=arm1176jzf-s -mtune=arm1176jzf-s"