Comment 23 for bug 576705

See also

https://sourceforge.net/tracker/index.php?func=detail&aid=2980549&group_id=1537&atid=101537

here a user succeeds with the S21 and Gutenprint 5.2.5 choosing the Epson Stylus C68 as their printer model. Please try. This could also help to identify whether this bug and the upstream bug are the same. You could perhaps also try the patches of the upstream bug.