git clone git://git.denx.de/u-boot.git
cd u-boot
git checkout v2017.01
source ../../MELP/Chapter02/set-path-arm-cortex_a8-linux-gnueabihf
make CROSS_COMPILE=arm-cortex_a8-linux-gnueabihf- am335x_boneblack_defconfig
make CROSS_COMPILE=arm-cortex_a8-linux-gnueabihf-