Thank you very much for your confirmations, lembas and miga.
I can, then, rest assured that there's nothing wrong with my WiFi connection.
As for the error messages display, lembas, the only one that appears during
boot is the "ssb0:0: Missing Free firmware" one.
So, there's no need to hide the other ones that you mention, and that only
appear written in the "dmesg" file.
Thank you very much for your help, anyway.
And, as for hiding that particular message, during boot, I guess I can try to
look for a solution elsewhere, since that's not a Trisquel-specific problem.
