Reliably reloading the calibration data of IMU BNO055
I found the solution. It is enough to add a function that when reperfoming the calibration of the magnetometer, checks ONLY if the magnetometer is calibrated (while the calibration for the accelerometer and gyroscope is reloaded from the EEPROM).

void performMagCal(void) {
  uint8_t system, gyro, accel, mag;
  system = gyro = accel = mag = 0;

  while (mag != 3) {

    bno.getCalibration(&amp;system, &amp;gyro, &amp;accel, &amp;mag);
    displayCalStatus();
    Serial.println("");
  }

  Serial.println("\nMagnetometer calibrated!");
}