Egyptian investigators have been trying for days to fix the memory chips, which would allow them to begin transcribing and analysing the recordings and data in pursuit of insight into what caused the crash.
The repaired black boxes will be returned to Cairo for analysis in Egypt’s aviation ministry laboratories, the committee previously said.
The Airbus went down in the eastern Mediterranean Sea en route from Paris to Cairo on May 19 and all 66 people on board were killed.
“Tests have been carried out… and we can be sure the flight parameters were properly recorded”, the investigators said.
Another black box, believed to contain conversations from the cockpit, is scheduled for repairs on Tuesday.
The restoration of the black box comes as French authorities opened a manslaughter investigation into the crash on Monday, saying that there had yet been no clear evidence that an act of extremism had downed the plane.
Prosecutor’s office spokesman Agnes Thibault-Lecuivre told the Associated Press news agency the inquiry was launched as an accident investigation. She said authorities were not favouring the theory that the plane was brought down deliberately.
Search teams have recovered its two flight recorders, which arrived in Paris on Monday, where technicians will attempt to fix them.
Amid speculation ranging from mechanical failure to terrorism, investigators are looking to extract any bytes of the data to find the critical evidence needed to reveal what caused the crash. Forty Egyptians were on board, as well as two Iraqis, two Canadians, and one each from Algeria, Belgium, Britain, Chad, Portugal, Saudi Arabia and Sudan.