Consider that this issue occurs from the beginning, I mean as soon as I switch the tv&decoder on so I don't think it's related to any "overwarming point" after X working minutes. Consider that sometimes (not always!) the video is still ok within the menu, I refer to the small video in the preview channel list so it's a weird scenario imho. Finally consider that some of these channels have a HD version (eg. ch22 "normal" -> ch522 hd) and their hd version videos still run ok. Definitely there's no recursing scheme for this issue.
Final users in that other forum called this "bug", due to its age or/and a sort of sequence of operations done by me, so I hoped I could solve that changing/fixing something that relies to its electronics; am I on the wrong way here?
recoding ROM could help,maybe
Do you mean to try with another fw? If yes, I've already tried. I've also tried a factory reset with no result, if this helps.