I contacted Yamaha Support for the following problem:
My SX900 would never update the indexes for the search function in Styles, Registrations, Midi, etc. So even though I removed the USB and gave it time to update, it would return results from the USB, then if I selected a search result, it would tell me the USB was not available. So search was completely broken. Even a factory reset didn't get rid of the problem.
Yamaha Support was quick to respond, and very supportive. After a month of working with them, they decided to pass the bug report to the development team, and replace my SX900. They would normally only replace the main board, but I live a couple of hundred miles from the nearest service center, and I think they want the "bugged" unit to send to development.
So if you have a SX700, SX900 or Genos that has search problems like I describe above, the support team would like to hear from you, as they want to know how this is happening.
Bottom line is that Yamaha has a first class support organization.
Craig