Possible? Have a friend with an older FW that he's sitting on and he wants to use the PS4 to play movies from USB. Methinks this isn't possible, what say ye?
And he didn't even bother to test it, but you decided to ask it here for no obvious reason? If it can't play a thing and he decided to sit out from the update, it's his problem, not yours nor ours.
(And I don't think this is hacking/homebrew related.)