Did you try the HD500 with the original firmware before updating?  Just curious - but if you did, did you notice any odd behaviour.  You may just have gone straight to the update which is also fine and shouldn't cause you any grief.

You can roll back to an older firmware version if you want to just to confirm whether the problem really is with the HD500 or whether it's a possible corrupted firmware installation issue.

The other thing you might want to look into is the stability and reliability of the power supply in your premises.  Most places are absolutely fine of course, but there can be instances where people live out in the country perhaps where sometimes power supplies from the national grid may not be quite as reliable as they might be in a city environment.   If that is a possibility for you, perhaps running your computer gear and digital gear like the HD500 from a battery backed UPS might resolve your issue BUT TBH that is an extreme measure to have to go to, and the chances are that your power supply is fine.

But for a new unit brand new out of the box I think it should pretty much just work, so if the issues persist, I'd be inclined to just take it back get the store to check it out and get a different one as necessary.

Nick