Agency chief Henry Bambang Soelistyo said people who reached the crash site yesterday had retrieved the cockpit voice recorder, but not the flight data recorder.
Soelistyo earlier said both black boxes had been recovered. But today, he said officials had misinterpreted reports from rescuers at the scene.
The cockpit voice recorder captures the pilots' conversations and any other noises in the cockpit, while the flight data recorder holds key details about the plane's speed, altitude, direction and the pilots' actions during the flight.
Heavy fog and bad weather have prevented the evacuation of bodies from the crash site by helicopter. Rescuers have had to take them on foot, walking through the rugged jungle for five hours to Oksibil. So far 27 bodies have been evacuated.