I have one doubt. Please tell if you know the answer or idea.

Actually, In own design flight controller, we use stm32f4 microcontroller. First, we upload px4fmu v4 bootloader. After that, we set airframe, radio calibration, Esc calibration, etc…

My question is,
Suppose if I again bootload controller previous calibration data should be erased.
But, In my case, if I bootload again, there was nothing erased, previous data will be there only.

I want to use the controller freshly. Is it possible?