Da Vinci Jr no longer communicating via usb how to use SD card?

For some reason the software can't find the USB port.  I tried using Cura on Linux but it's doing the same.  The hardware is being found, but attempts at communicating with it fail.  It never replies. 

So I'd like to upgrade the firmware somehow. 

My attempts at generating a .3w file from gcode have not been successful. 
I have read reports that a .3w file is a base64 file, but the SAMPLE.3w file on my SD card is definitely not a base64 formatted file.

If I can figure out how to convert a gcode file to .3w I can write it to the SD card.

Otherwise, I'm out of luck with a large piece of plastic junk.  It just stopped communicating one day.

Thanks,
Jim