What does it enumerate as? My guess is that you would at least need to edit the .inf file and insert the VID/PID pair that the board uses. Looking at that PCB, I suspect the little SOT23-5 chip marked 'M0M9' is an I2C EEPROM that sets the parameters for the USB chip. The CPLD is going to be taking the data out of the chip (which is parallel) and reformatting it so it can be connected to Nintendo's serial EXI bus (which is basically SPI plus an interrupt line). Since the boot disc has been dumped and the way the EXI works is pretty well documented it shouldn't be too difficult to figure out what the CPLD is doing and write some equivalent HDL.