diff --git a/boards/opencm9-04/board.c b/boards/opencm9-04/board.c
index 3e73deabbe28510af67e1eec7a762e22d3ee7e3a..4c049ffee91bfccf3a9325abb8fbdacb78ac08ba 100644
--- a/boards/opencm9-04/board.c
+++ b/boards/opencm9-04/board.c
@@ -34,6 +34,9 @@ void board_init(void)
     /* disable bootloader's USB */
     RCC->APB1ENR &= ~RCC_APB1ENR_USBEN;
 
+    /* disable bootloader's TIMER update interrupt */
+    TIM2->DIER &= ~(TIM_DIER_UIE);
+
     /* configure the RIOT vector table location to internal flash + bootloader offset */
     SCB->VTOR = LOCATION_VTABLE;
 }