Jog dial control buttons on Olympus OM-D E-M1 twitchy or sticky

I have the above camera which works well, but when I need to access the menus via the "jog dial" / buttons, they either stick and need extra pressure to regiter a push, or are super-sensitive and react too fast (like a double-click...) .

I suspect that the buttons are slightly loose or mis-aligned behind the case. I'd like to open the back of the housing to verify / repair / tighten / clean the buttons.

Does anyone have info about the procedure to remove the case / housing ?

Thanks!