Plumax 525U2-PCB enclosure

I’m only burning coasters with my new Plextor 712A writer. It sits in a new Plumax 525U2-PCB enclosure (USB2.0) and connect to my Dell Latitude 640C laptop through a new noname USB2.0 PCMCIA card (NEC chipset). As one of the troubleshooting steps, I would like to upgrade the firmware in the Plumax enclosure; I believe it uses the Cypress chipset. I have not been able to find any firmware upgrade for this enclosure. Would anybody have a tip for me?