AFAIK, none. Recently Lattice updated their licensing forbidding reverse engineering, but changed their mind once the community complained. Also, a while back

AFAIK, none. Recently Lattice updated their licensing forbidding reverse engineering, but changed their mind once the community complained. Also, a while back, lattice added support to something that was already implemented on the open source tools, but with a different name -- thus, code that worked on open source don't work on the official tool. (I'm not sure if this was "fixed"). The open source tools have been create by hard work of many hackers. If you want to know more, watch this 35C3 talk [1] where MathiasL describes how they reverse engineered the Artix-7 bitstream. Last time I checked, Symbflow [2] only supported Lattices FPGAs and Artix-7 (smallest fpga from Xilinx 7-series). Both are quite small FPGAs. [1] https://www.youtube.com/watch?v=Y1Wwa8csFjk https://www.youtube.com/watch?v=Y1Wwa8csFjk [2] https://symbiflow.github.io/ https://symbiflow.github.io/