U-Boot
From Rockchip open source Document
U-Boot Guide
Contents
Download U-Boot
Upstream U-Boot
You can clone the u-boot repository by running:
git clone git://git.denx.de/u-boot.git
Alternatively you can use u-boot-rockchip instead which may with some patches not get in mainline:
git clone git://git.denx.de/u-boot-rockchip.git
Rockchp U-Boot
You can clone the u-boot repository by running:
git clone https://github.com/rockchip-linux/u-boot.git
Supported Devices
Configure U-Boot
Build U-Boot
Get a toolchain
If you haven't done so before, get a suitable toolchain installed and added to your PATH.