Are you recording video normally to your Mini 4? My mini was hit by the failure to cache videos bug and I have tried reflashing .600. Rolling back to DJI Go4 v4.06, downflashing to firmware .400 then .550 and still no video. Going to see if there is a complete reset option and try that nextUpgrade went through easily and after several flights I can't find any faults in the new firmware yet. All is good.