Firstly, I get great results from the HP Pro Matte Canvas using the built-in profile. It is a very matte finish though, and unvarnished can give that 'rubbed' effect you describe. I recommend varnishing. Also, have you printed anything since calibrating it?
BTW, I've never heard of the formatter board freaking out when upgrading firmware. Some of the boards did come with faulty Hitachi hard drives that caused problems - if you have issues, contact HP straight away and they will replace it.
When my Z3100 packed it in last month, it was AFTER I downloaded and installed a printer profile for HP Pro Matte. Everything was fine until I did that. HP Tech support asked me if I had updated the firmware first (what?).
A replacement formatter solved the problem.