Current work focuses on further improving our timing analysis flow. How do I use the Fully Open Source iCE40 Flow? Synthesis for iCE40 FPGAs can be done with Yosys. Place-and-route can be done with arachne-pnr. Here is an example script for implementing and programming the rot example from arachne-pnr (this example targets the iCEstick development board): yosys -p "synth_ice40 -blif rot.blif" rot.