I discover that the Intel WiFi card that came with my System76 Pan7 was not free, so I just order a mini pcie card from http://libre.thinkpenguin.com and it work perfectly.
Since I don´t like the two DE available as default, initially I install Lxde and then Xfce which work after some tweaking, but at the end just decide to do a netinstall. As a side note: Just by change, a week before installing Trisquel I bought an HP deskjet-2050-j510 printer that happen to have free drivers so that was defensively good news for me. At the end the Mini Pcie card issue was not a problem, but rather just a discovery on how free my laptop was.
