This may be over by now, but there was a warning from Oly about the updating "killing" or "bricking" some EM-5's
No, I don't have this documented, but would rather tell you to check on this before you have a problem. I saw the reference to the warning over on www.fourthirdsphoto.com
Here is the text from the warning post earlier today:
Default Re: E-M5 firmware update version 1.2
Warning Folks, advice from Olympus Europe is not to do the update for the time being as it seems to have been killing too many cameras.
I don't know if this also applies to the US.
This came to light on e-group HERE not from the Olympus update page where it is still listed.
I can't imagine why they haven't pulled it until the issues are resolved.
Personally I completed the update successfully before Ian posted about the problem.