Debug is working but not run modus with STM32F746

the main looks like this:

int main(void)
{

  /* USER CODE BEGIN 1 */
  SystemCoreClock = 200000000;
	SystemCoreClockUpdate();
//	EventRecorderInitialize (EventRecordAll, 1);  // initialize and start Event Recorder
//	EventRecorderStart();
  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */
	//HAL_Delay(2000);
  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_FMC_Init();
  MX_LTDC_Init();
  MX_TIM3_Init();
  MX_LWIP_Init();
  /* USER CODE BEGIN 2 */
	//HAL_Delay(2000);
	initTouchDisplay();
	
	api_fadein_graphics();
	
//	HAL_Delay(2000);
//  MX_LWIP_Init();
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
		lv_timer_handler();
		lv_tick_inc(HAL_GetTick() - lv_tick_get());
		MX_LWIP_Process();
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

Perhaps the problem is in addresses, therefore I list the configuration (the LWIP_RAM_HEAP_POINTER was added manualy as user constrant in CubeMX, because is missing in STM32CubeMX Version 6.11.1):

// in ethernetif.c:
__attribute__((at(0x2004fa00))) ETH_DMADescTypeDef  DMARxDscrTab[ETH_RX_DESC_CNT]; /* Ethernet Rx DMA Descriptors */
__attribute__((at(0x2004f000))) ETH_DMADescTypeDef  DMATxDscrTab[ETH_TX_DESC_CNT]; /* Ethernet Tx DMA Descriptors */

// in main.h:
#define LWIP_RAM_HEAP_POINTER 0x20040000

okay the problem is eliminated by actvating checkbox "Use MicroLIB" in Options for target. But why? Can be discribed what the purpouse of that LIB?