Linkit Smart 7688 + WM8690 DAC

Recently I bought LinkitSmart 7688 board. It is few years old, so it was shipped with out of date stock firmware, based on OpenWRT. I was able to found modern build for this device:

It works fine, however there is one issue. I also bought a breakout board equipped with WM8960. I'd like to use it to play audio on LinkitSmart. Is there a way to add proper module/driver to already installed system or do I need to recompile firmware and reflash board with custom build?
Is there some detailed description. Page linked above (with modern version of OpenWRT for Linkit) mentions audio, but I do not understand it. What should I do to have working DAC?