u-boot compiler for Ocean devices, forked off u-boot-sunxi (https://github.com/linux-sunxi/u-boot-sunxi)
To compile, generate the config.h and then make the .bin file.
Note: The config.h file has already been created. Unless you know what you are doing, please skip this step.
To generate config.h, run
# <BOARD_CONFIG> is the name of the board you are compiling u-boot
# BlueOcean is a fork of Cubietruck, so in this case, this would be 'Cubietruck_config'
make CROSS_COMPILE=arm-linux-gnueabihf- <BOARD_NAME>_config
This generates include\config.h and includes all the necessary header files.
To generate .bin image, run
make CROSS_COMPILE=arm-linux-gnueabihf- -j4