After cloning this repo to your local maschine, update the git submodules.
cd org.muhkuh.tools-hboot_image_compiler
git submodule init
git submodule update
Next, build it with python2, this will take a while, so better get a cup of fresh hot coffee.
python2 mbs/mbs
After a while the resulting zip file should be located in:
./targets/repository/org/muhkuh/tools/hboot_image_compiler/CURRENTVERION/
Where the CURRENTVERION is the something like 0.0.1.2