6.1 Get X Linux Source Code (based fast as iTOP-399 development board)
First Web site to download from the fast to the Linux source provides, after the downloaded source code file directory follows: 
Then use source decompression tool decompression obtained, as shown below: 
After extracting rk3399_linux_sdk_v2.0_191209.tar.gz generating compressed, as shown below:
拷贝解压生产的 rk3399_linux_sdk_v2.0_xxxxxxxx.tar.gz（xxxxxxxx 代表
源码的发布日期）文件到 Ubuntu 系统，然后在 Ubuntu 系统下解压，如下图：
解压完成后，得到文件夹：rk3399_linux_sdk_v2.0_191209，如下图：
6.2 安装 x Linux 源码依赖包 源码依赖包
使用如下命令安装所需的软件包：
1、sudo apt-get update
2、安装 kernel 及 uboot 编译需要依赖的软件包
sudo apt-get install git-core gnupg flex bison gperf
build-essential zip curl zlib1g-dev gcc-multilib g++-multilib
libc6-dev-i386 lib32ncurses5-dev x11proto-core-dev libx11-dev
lib32z1-dev ccache libgl1-mesa-dev libxml2-utils xsltproc unzip
device-tree-compiler liblz4-tool
3、安装 Buildroot 编译需要依赖的软件包
sudo apt-get install libfile-which-perl sed make binutils gcc g++
Patch gzip bzip2 tar perl bash cpio Python the unzip rsync File bc libmpc3
git repo texinfo texinfo pkg-config cmake Tree
3 6.3 x Linux source code compiler source code
as a whole 6.3.1 compiled
using the cd command to enter the rk3399_linux_sdk_v2.0_190805 folder.
Compile four command
1. ./build.sh BoardConfig.mk 
2. All ./build.sh 
3. Firmware ./build.sh 
4. ./build.sh updateimg ' 
finally generated image file update in rocdev directory. img.
6.3.2 compiled separately
command ./build.sh -h to see the optional parameters
Separately compiled uboot: ./build.sh uboot
Generating in the u-boot.bin uboot directory.
Separately compiled kernel: ./build.sh kernel
generated at boot.img kernel directory
separately compiled rootfs: ./ build.sh rootfs
generated at rootfs.ext4 buildroot / output / rockchip_rk3399 / images directory