.

.

.

$ sudo apt-get install gcc-arm-linux-gnueabihf
$ sudo apt-get install g++-arm-linux-gnueabihf
$ sudo apt-get install device-tree-compiler

.

.

.

$ sudo apt-get install git
$ git clone git://git.denx.de/u-boot.git
$ git checkout v2017.01

.

.

.

KBUILD_CPPFLAGS := -D__KERNEL__ -D__UBOOT__ \
                   -save-temps=obj

KBUILD_CFLAGS   := -Wall -Wstrict-prototypes \
                   -Wno-format-security \
                   -fno-builtin -ffreestanding \
                   -save-temps=obj
KBUILD_AFLAGS   := -D__ASSEMBLY__ \
                   -save-temps=obj

.

.

.

$ make rpi_3_32b_defconfig 
$ make -j4 ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf-