diff --git a/bsp/stm32/libraries/HAL_Drivers/drv_common.c b/bsp/stm32/libraries/HAL_Drivers/drv_common.c
index f150d81fefe77b691ce9c69fc9881a5db7f56a3d..bf7ed20e94d0bca3101ee51da3afaa6416b63876 100644
--- a/bsp/stm32/libraries/HAL_Drivers/drv_common.c
+++ b/bsp/stm32/libraries/HAL_Drivers/drv_common.c
@@ -30,7 +30,7 @@ void rt_hw_systick_init(void)
 #if defined (SOC_SERIES_STM32H7)
     HAL_SYSTICK_Config((HAL_RCCEx_GetD1SysClockFreq()) / RT_TICK_PER_SECOND);
 #elif defined (SOC_SERIES_STM32MP1)
-	HAL_SYSTICK_Config(HAL_RCC_GetSystemCoreClockFreq() / RT_TICK_PER_SECOND);
+    HAL_SYSTICK_Config(HAL_RCC_GetSystemCoreClockFreq() / RT_TICK_PER_SECOND);
 #else
     HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq() / RT_TICK_PER_SECOND);
 #endif
@@ -71,7 +71,17 @@ void HAL_ResumeTick(void)
 
 void HAL_Delay(__IO uint32_t Delay)
 {
-    rt_thread_mdelay(Delay);
+    if (rt_thread_self())
+    {
+        rt_thread_mdelay(Delay);
+    }
+    else
+    {
+        for (rt_uint32_t count = 0; count < Delay; count++)
+        {
+            rt_hw_us_delay(1000);
+        }
+    }
 }
 
 /* re-implement tick interface for STM32 HAL */
@@ -90,7 +100,7 @@ void _Error_Handler(char *s, int num)
 {
     /* USER CODE BEGIN Error_Handler */
     /* User can add his own implementation to report the HAL error return state */
-    while(1)
+    while (1)
     {
     }
     /* USER CODE END Error_Handler */
@@ -107,10 +117,12 @@ void rt_hw_us_delay(rt_uint32_t us)
     start = SysTick->VAL;
     reload = SysTick->LOAD;
     us_tick = SystemCoreClock / 1000000UL;
-    do {
+    do
+    {
         now = SysTick->VAL;
-        delta = start > now ? start - now : reload + start - now;
-    } while(delta < us_tick * us);
+        delta = start >= now ? start - now : reload + start - now;
+    }
+    while (delta < us_tick * us);
 }
 
 /**
diff --git a/src/scheduler.c b/src/scheduler.c
index 677be6cff776f4ee13c22a949bd62f088f5345b2..06f305ea0b0ba6a49c3200a07d49e5d68f4daf1f 100644
--- a/src/scheduler.c
+++ b/src/scheduler.c
@@ -43,7 +43,7 @@ rt_uint8_t rt_thread_ready_table[32];
 #ifndef RT_USING_SMP
 extern volatile rt_uint8_t rt_interrupt_nest;
 static rt_int16_t rt_scheduler_lock_nest;
-struct rt_thread *rt_current_thread;
+struct rt_thread *rt_current_thread = RT_NULL;
 rt_uint8_t rt_current_priority;
 #endif /*RT_USING_SMP*/