I had exactly the same problem yesterday:
1) The instructions are rubbish. In order for the update process to start at all, you have to 1. press the button briefly (the menu appears), then 2. hold the button in the "down" direction for about 10 seconds, then the update process starts (this is not so clear in the manual).
2) When the update process started (file is being searched for), it still didn't recognise the various sticks or the file, and nothing happened.
If anyone has any input, I would also be very grateful.