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
cd rkdeveloptool
autoreconf -i

Now you have rkdeveloptool executable at the current directory.