Ian,
How long ago was that?

If Yamaha can fix this they sure should...so, either they just don't think it's a big enogh issue for a 'home' keyboard or they can't fix it because of HW or OS limitations. Most likely HW.
If enoghh folks returned keyboards because of this issue...that may change the response from them (But only if the reason for returns actually gets back to the high level management).
Lee S.