HAL_Delay hangs after jumping from bootloader to FreeRTOS app (using TIM14 as tick source)

[SaiKumar1]

Hello,

I am working on an STM32F446RE with a custom bootloader and FreeRTOS application.

• Bootloader address: 0x08000000

• Application address: 0x0800C000

• The bootloader successfully jumps to the application by setting MSP, PC, and SCB->VTOR.

• In my application, I configured FreeRTOS to use a hardware timer (TIM14) instead of SysTick as the OS tick source.

Problem:
When I flash the application directly, it runs fine.
But when I run through the bootloader, the application stops working as soon as it calls HAL_Delay(). If I comment out HAL_Delay(), the app continues normally. After the RTOS kernel starts, I get a HardFault on the first interrupt.

I suspect this is related to SysTick still being dirty from the bootloader, while my application is configured to use TIMx as the tick source.

My questions:

1. What is the recommended way to cleanly reinitialize the HAL tick and interrupt system after jumping from a bootloader to an application that uses TIMx instead of SysTick?

2. Should I override HAL_InitTick/HAL_GetTick in the application so that HAL_Delay() works with FreeRTOS (using TIMx ticks)?

3. If HAL_Delay() must work before FreeRTOS scheduler starts, should I explicitly reconfigure SysTick in the application even though FreeRTOS uses TIM14?

4. Is there a recommended sequence of peripheral deinitialization in the bootloader to avoid SysTick/interrupt leftovers?

Extra info:

• Toolchain: GCC (CubeIDE, no optimizations)

• Bootloader disables SysTick (SysTick->CTRL=0; SysTick->LOAD=0; SysTick->VAL=0;) before jump.

• Application runs fine standalone, fails only after bootloader jump when HAL_Delay() is called.

Thanks in advance for guidance.

[NicRoberts]

Isn't it recommended that you leave SysTick to FreeRTOS & designate a separate TIM for HAL use?

[SaiKumar1]

Yes, I am aware that FreeRTOS normally takes over SysTick, and the recommendation is to keep SysTick for FreeRTOS while designating a separate hardware timer for HAL timebase.In my case, I configured FreeRTOS to use a hardware TIM (not SysTick) for the RTOS tick source. That’s why HAL_Delay() is failing after bootloader jump — because Cube HAL by default still expects SysTick to be running for delays, unless HAL_InitTick is overridden.

[TDK]

> When I flash the application directly, it runs fine.
> But when I run through the bootloader, the application stops working as soon as it calls HAL_Delay().

Ensure SCB->VTOR is being set correctly by the application. When it hard fault, see what interrupt it thinks it's in (VECTACTIVE bits in SCB) and address the problem appropriately.

[SaiKumar1]

I am working with a custom bootloader on STM32F446RE.

The bootloader successfully jumps to my application at 0x0800C000.

The application runs, prints "Application Running", but as soon as it calls HAL_Delay(), the code stops executing.

If I flash the application directly (without bootloader), it runs completely fine.

In my jump code, I de-initialize peripherals, disable SysTick, clear pending interrupts, reset NVIC, and then relocate the vector table before jumping. Example:

void jump_to_application(void)

{

    uint32_t appStack        = *(volatile uint32_t*)APP_START_ADDR;

    uint32_t appResetHandler = *(volatile uint32_t*)(APP_START_ADDR + 4);

    typedef void (*pFunction)(void);

    pFunction JumpToApp = (pFunction)appResetHandler;

    __disable_irq();

    SysTick->CTRL = 0;

    SysTick->LOAD = 0;

    SysTick->VAL  = 0;

    for (uint32_t i = 0; i < 8; i++) {

        NVIC->ICER[i] = 0xFFFFFFFF;

        NVIC->ICPR[i] = 0xFFFFFFFF;

    }

    HAL_UART_DeInit(&huart2);

    HAL_DeInit();

    HAL_RCC_DeInit();

    SCB->VTOR = APP_START_ADDR;

    __set_MSP(appStack);

    __enable_irq();

    JumpToApp();

}

The code will jump from bootloader to app on pressing the button PC13 configured as EXTI 

void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)

{

if(GPIO_Pin==KEY_Pin)

{

jump_to_application();

}

}

and my app code is very simple just to print a small text on uart2,

  while (1)

  {

  Log_Msg("Application Running\r\n");

  HAL_Delay(1000);

    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */

  }