Questions about compass safety and logs

few people, in the french group ph2.1 aka “the cube”, asked if we use only one compass (on a copter) and we accidentally tick externally mounted (on compass calibration page) but we don’t have an external compass, what happens ? does the prearm check switch to a internal compass? or it just warns us to don’t fly the copter (or stop the arming of the copter)?

For the logs, when i check them, i never have the date of the flight (there is just writen 01/01/2000) how we configure that to have the day of their creation ?
thank you :slight_smile: