1) install packages you would need for building what we need.
sudo apt-get update
sudo apt-get install -y git lzop build-essential gcc bc libncurses5-dev libc6-i386 lib32stdc++6 zlib1g:i386
2) get proper toolchain for building
sudo mkdir -p /opt/toolchains
wget https://releases.linaro.org/components/toolchain/binaries/6.3-2017.05/aarch64-linux-gnu/gcc-linaro-6.3.1-2017.05-x86_64_aarch64-linux-gnu.tar.xz
sudo tar Jxvf gcc-linaro-6.3.1-2017.05-x86_64_aarch64-linux-gnu.tar.xz -C /opt/toolchains/
3) set export variables properly
export ARCH=arm64
export CROSS_COMPILE=aarch64-linux-gnu-
export PATH=/opt/toolchains/gcc-linaro-6.3.1-2017.05-x86_64_aarch64-linux-gnu/bin/:$PATH
cd u-boot
./make.sh odroidgo2
cd sd_fuse
./sd_fusing.sh <device/path/of/your/card>
cd kernel
make marsboard_defconfig
make
kernel image: arch/arm64/boot/Image
kernel dtb: arch/arm64/boot/dts/rockchip/rk3326-marsboard-linux.dtb