I got a problem with my 55PFL8007T/12. When zapping to a new channel the screen goes black, but the sound is ok. To get the picture back I have to turn the TV off and on. I am not sure, but think it came with the upgrade to QF1EU- (20012-10-24). I used the TV to do the upgrade for me as it told me to do so. No error messages and it said all was done ok. This is very ennoying as the TV is not even 1 month old. My guess is that it's a SW problem. How can this be tested? Is it possible to do a downgrade or reset?