If that is really the case, I would have expected the passengers to have collectively sent text messages informing friends or relatives that "omg, loud noise, lights went off!".
4 minutes would be plenty of time to send messages.
We would have read this information much sooner after the crash, ergo I don't believe there was a power loss.
I fear the data was deleted by some party.
The Boeing 737-800 has batteries that power certain things in the event of a dual engine failure, including cabin lighting.
Those same batteries, on 737s manufactured more than about 15 years ago, do not provide backup power to the flight data recorder or cockpit voice recorder.
In the event of power loss, the data and voice recorded have lower priority than cabin lighting?!
And the cherry on top is that this was the case on 737's until ~ 2010?!
Defusing my bullsh!t alarm with a second layer of bullsh.t?
I would swallow it all ad fundum if you can provide HN with reliable links to manuals, procedures, ... describing how electrical energy for the passenger cabin is prioritized over the data and voice flight recorders!