source:
Investigators Encounter Difficulty Extracting Data From A400M Flight Recorders | Defense content from Aviation Week
The recorders have been transfered to Paris. French General Bruno Caïtucoli, head of BEA's defense division, reports "technical issues in reading the system". That's using an extracting system provided by the French military
Direction Générale de l'Armement.
We don't even know if the FDR, CVR, or both, are affected.