I believe that the QCN file holds the non-volts memory including the PRL, logo, and your ESN. I don't think you can replace it, but with KWPST you should be able to change virtually anything in it.

It is more then likely just the PRL that is wrong, since otherwise the phone is working, so if you can get the PRL files for Sprint (possibly for another Kyocera phone on their network. I don
't know if they are manufacturer specific) it should be possible to load it onto your phone with KWPST.

Alan