BEA will probably analyze flight recorders: (from their twitter account @BEA_Aero) :
⚠️ 03/10 accident to the #Boeing737Max @BoeingAirplanes ET-AVJ operated by @flyethiopian / Ethiopian authorities have requested @BEA_Aero assistance for the analysis of FDR & CVR / Any communication on the investigation progress is the responsibility of those authorities.