Well...
I've tried every kernel available in the Trisquel repository, in several of
its ("-32", "-48" etc) variants, and also every kernel in jxself's
repository, and the best that I can get, is the boot splash screen, with
kernel 3.4.64-gnu1, from the latter repository, but then a black screen, when
it should show the log in screen.
And, checking the correspondent Xorg log, for this last best attempt, I can
see the familiar "[mi] EQ overflowing" messages, again.
So, it seems like there's no way of, for now, having this graphics card
working with the nouveau driver...