tested all the stm32f4 board, work great

hw/bsp/stm32h743nucleo/board.mk

@@ -39,3 +39,10 @@ INC += \
 # For TinyUSB port source
 VENDOR = st
 CHIP_FAMILY = synopsys
+
+# Path to STM32 Cube Programmer CLI, should be added into system path
+STM32Prog = STM32_Programmer_CLI
+
+# flash target using on-board stlink
+flash: $(BUILD)/$(BOARD)-firmware.elf
+	$(STM32Prog) --connect port=swd --write $< --go

hw/bsp/stm32h743nucleo/stm32h743nucleo.c

@@ -158,6 +158,7 @@ void board_init(void)
   GPIO_InitStruct.Alternate = GPIO_AF10_OTG2_HS;
   HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 
+  // LED
   __HAL_RCC_GPIOB_CLK_ENABLE();
 
   GPIO_InitStruct.Pin = LED_PIN;
@@ -166,6 +167,7 @@ void board_init(void)
   GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
   HAL_GPIO_Init(LED_PORT, &GPIO_InitStruct);
 
+  // Button
   __HAL_RCC_GPIOC_CLK_ENABLE();
   GPIO_InitStruct.Pin = BUTTON_PIN;
   GPIO_InitStruct.Mode = GPIO_MODE_INPUT;