With no reply from Cymatic’s query form, and reading through other Cymatic user’s posts, it’s been a frustrating time, losing faith in the product and the company, but I have found an answer to my own problem that may help other users, and it’s the simple one in the topic title:
The USB mode works after removing the flash drive from the front USB socket.
That’s as far as I’ve got right now, but it takes just a few seconds to write it and could save the weeks of uncertainty and disappointed frustration with the product.
Hope it helps someone.
N.B Mini Flash drive used for playback only. Less risk of damage, stays in unit during transport.