I own a JTV69US. I love this guitar but this monkey-business is ridiculous.
I have version 1.82b.
Using the supplied cable and tried a standard CAT5 cable.
My guitar is plugged in.
My volume is turned up.
I'm USB plugged into the back of my Mac, not a hub or keyboard.
Everytime I try to upgrade or rollback the flash I get the error message ...
"Update Failed.
(Code 80009000) Unknown MIDI Error.
Make sure the cables are connected and try the update again."
I've tried it 3 or 4 hundred times. Same error message.
I own a 600 and 700 and have connected them many times (though there are usually some issues.) I've never been able to connect my JTV.
HELP!