Thanks Doug.? I just sent them an e-mail this morning, so perhaps they can offer some possible solutions.?
I think my best bet is to buy an official Xiegu USB/Serial cable, and then if that doesn't work I'll pursue re-flashing the bootloader over JTAG.
Unfortunately, I haven't had any success yet in finding a dealer in the USA that has the cable in stock right now.
Eric W1JH