I have the Fuji X-PRO1, updated the camera, with no lens attached. The update went without a glitch. I then updated my XF35mm F/1.4, also without a glitch. The correct firmware version was displayed on the camera, for both updates.
I read on Fujirumors that some people noticed more noise and slower autofocus after the update and that the version number did not show correctly , I did not experience any of that on my camera/lens.
My subjective non scientific feelings about these updates, after trying the X-PRO1 with the XF35mm, XF18mm and the XF60mm, are..
I think the camera seems more responsive, faster. The autofocus too, seems better on all the lenses. I have only tried in good lighting conditions, still some hunting in low contrast areas, but overall I would say this is an improvement.