Will it say 'Allahuakhbar' and if it does will we be told?recovered today, damaged but intact.
Will they show that the plane went down due to terrorism? And if they do, will we be told the truth?
In a statement, investigators said: "The vessel's equipment was able to salvage the part [of the recorder] that contains the memory unit, which is considered the most important part of the recording device."
The recorder will now be taken to the Egyptian city of Alexandria to be studied.
The plane's manufacturer, Airbus, previously said that finding the black boxes was crucial to understanding what happened when radar lost track of MS804.
Electronic messages sent by the plane revealed that smoke detectors went off in the toilet and the aircraft's electrics, minutes before the radar signal was lost.
According to Greek investigators, the plane turned 90 degrees left and then 360 degrees to the right, dropping from 11,300m (37,000ft) to 4,600m (15,000ft) and then 3,000m (10,000ft) before it was lost from radar.
A terror attack has not been ruled out but no extremist group has claimed to have downed the plane.
Analysts say human or technical error is also a possibility.
The crew on board do not appear to have sent a distress call.
The cockpit voice recorder should allow investigators to hear what the pilot and co-pilot were saying to each other, plus any alarms in the background.
If the flight data recorder is recovered, it should show what the plane's computers were recording at the time.
Experts have warned that signals emitted by the data recorder are expected to expire by 24 June.That's next Friday. Meanwhile, there are very few clues.
The little evidence so far suggests a fire broke out in the front of the aircraft, so they will be keen to film and photograph that area. One experienced investigator who worked on the Lockerbie bombing told me bomb damage looks very different to fire damage.I'm sure it does. But everything I've seen about this one seems to point to terrorism.