JVC LT-43N585 stuck on logo after power cut - where to find USB recovery firmware?

A TV’s firmware rarely behaves as it should when there’s a power cut. Try resetting the TV. First, try a ‘soft reset’ by simply unplugging the power lead from the socket, waiting a minute, and then plugging it back in. If this doesn’t work the first time, try it a second or third time. If a soft reset doesn’t work, it’s time for a hard reset: unplug the power lead from the socket, press the ‘Power’ button on the TV’s casing and, whilst holding this button down, plug the lead back into the socket. Keep the ‘Power’ button pressed for a further 30 seconds or so until the TV restarts.

Or could such a thoughtless ‘reset’ of the TV cause further damage to the data in the memory???
If it’s stuck on the logo, data corruption is very likely.
You’ll be lucky if the procedure for loading updates into memory works; if not, you’ll have to use other methods.