I have an LG dvd player connected to my TV. It plays most dvds without problem, however sometimes the movies has places where the scenes go dark then return to normal lighting. I noticed this with another player as well. My current problem is it won't recognize a dvd that it previously read. No I have not done any firmware upgrades, I just finished watching a blu ray movie went to put a second dvd in and it will not read it.
I use a laser lens cleaner from Philips, it looks like a dvd only it has two small brushes on the botom it works great on my old Lite-on dvd player/recoder, I use it after 20 moves and have had no problems reading the dvds.