Wow!
may be useful for others who are going to buy from digikey or amazon.com the last Parallellas .
At the end, after some attempts with different images, having tested Parabuntu-2016.11.1-hdmi-z7010, then previous recent versions, tha last attempt with
Ubuntu14.04-hdmi-z7010-2014.06.11 with esdk 5.13.9.10
was finally fully working .
SO, I finally had a chance to see on my HDMI monitor what I never saw from parallella-examples :
para-para
aobech
mandelbrot
....
and I discovered a full Ubuntu/Linaro version is available with this version of img for Parallella (15Gb of space).
The gap or price paied is that the sdk is at old version if compared with last Adapteva img.
But I could have all the examples working even if with different SD cards.
May be the problem is COPRTHR 1.6 not working with last image ?