@Emmanuel-Goudot I sincerely hope Pycom will release the schematics. I have asked them a few times now and no response. IMHO This will do more harm than good for Pycom. It is not rocket science and it is crazy I see so many posts on people trying to reverse engineer the board(s) and even patch the firmware of the PIC by hand? The documentation is not complete or different depending on what file you read. To much time is already spend on finding out all the connections and how it works and even then it is not sure if it is correct or what side effects are possible. PYCOM: let us help you, there is a big community of enthusiastic users that can help you forward. I just finished comparing pysense/track/lopy wiring diagrams to find out which pins can be used.