I've now come up empty. The only slight hope I have is to wait for the battery to die out and see if I can connect it to the USB. Since I can't connect it to the USB, I obviously can't get the firmware successfully on the memory. *sigh* Great.
Got the firmware to start upgrading but isn't completing. Will leave it doing it overnight but I really don't have high hopes. I think I must of destroyed the OS on the Dingoo and I can't get it back on.