I think its the last two hours before the crash. I'm pretty sure they wouldn't record the last 2 hours before the batteries died.
Anywho, latest I read, I heard that the batteries have died and haven't heard any pings for the last few days. Article I read, they next need to send down a sub to where they think they heard the pings. Could be a couple more months they said. Who knows where that plane ended up. Lets just say aliens and call it a day.