You need to compile the firmware from source, see https://github.com/pingdynasty/OwlWare
There are two files: factory.h and factory.cpp that need to list the includes and definitions of the patches you want to include. Edit these files, make sure that all patches are available and compile the code.
However because the patch API has changed over time you need to also make sure that the patches and the firmware are compatible. The code is not quite up to date because we've been working on the next generation firmware, where all patches are dynamically loaded and stored. You can find this code here: https://github.com/pingdynasty/OpenWare