So, after reflashing the device, in order to try to get extmou to work, since I had a problem in the bluetooth stack, I can tell you extkbd is unable to properly generate portuguese diacritics.;the layout doesn't match SU-8W's one,

If you want, I can upload that custom SU-8W layout to you, freemangordon, so you might implement it. I'm going back to setxkbmap for now.