Sounds more like a hardware issue to me, but if it is there’s really no way to fix it short of getting a new player. Is that the only button that doesn’t seem to work right? What if you just give it a quick press, anything?
Re-installing the firmware may do the trick, but it may not. Still, it can’t hurt to try. Here is the firmware post with the latest version. Don’t use the Updater; just follow the manual insstallation instructions.
Let us know how it goes.
