troubleshooting: how to reset the Olympus OM-D E-M5 if it stops working
(from: http://ayton.id.au/wiki/doku.php?id=photo:olympusem5_reset)
see also:
introduction
menu driven factory reset
this will lose nearly all of your settings but keep date and time [menu], [camera1], [reset/Myset], [Reset]
hidden hard factory reset
this will lose all of your settings including date and time Power on with [menu] held down When LCD lights, release [menu] press the following sequence: [menu], [down] to spanner, [right], [down] to LCD brightness, [right] [info] [ok] now for the actual reset: Hold [menu]+[ok] together for a few seconds to get the hardware reset screen. [ok] to proceed.