Paste the file to SD card, rename to ZNP_ROBIN_NANO.bin
, insert into the printer and restart it.
You might need to update the screen too, I haven't tested it on version 1.4, you can find 1.5 here
I noticed that Linear Advance values needed to be recalibrated, since the values I was using before were too high now
Only tested this on Neptune 3 Pro, but Plus and Max should work too, make sure to pick the correct firmware.
Use at your own risk, I only tested this on my own printer