To flash ROCK960 board, you need to install the rkdeveloptool, which is an open source cross platform command line tool. To build rkdeveloptool, follow the instructions below:
Install build tools:
sudo apt-get install libudev-dev libusb-1.0-0-dev dh-autoreconf
Clone the source code and build:
git clone https://github.com/rockchip-linux/rkdeveloptool
cd rkdeveloptool
autoreconf -i
./configure
make
Now you have rkdeveloptool executable at the current directory.