There are threads explaining how to boost the RC using DJI GO, and even how to use 2.57Hz by modifying a configuration file.
But What about Litchi?
How can I get my Mavic Pro use the 2.57GHz when flying with Litchi?
Sorry but I cannot answer your question (I would also like to know) but I can say that Litchi and Go4 do not get on well together. I am not sure about the boosted Go but at the very least I would close Go4 by dragging it off the screen. I usually go one step further and reboot my tablet if Go has been running on it before launching Litchi.