diff --git a/lib/stm32/common/usart_common_all.c b/lib/stm32/common/usart_common_all.c
index 4e42f2a9..5c411779 100644
--- a/lib/stm32/common/usart_common_all.c
+++ b/lib/stm32/common/usart_common_all.c
@@ -50,13 +50,12 @@ void usart_set_baudrate(uint32_t usart, uint32_t baud)
 {
 	uint32_t clock = rcc_apb1_frequency;
 
-#if defined STM32F2 || defined STM32F4
-	if ((usart == USART1) ||
-	    (usart == USART6)) {
-		clock = rcc_apb2_frequency;
-	}
-#else
-	if (usart == USART1) {
+#if defined USART1
+	if ((usart == USART1)
+#if defined USART6
+		|| (usart == USART6)
+#endif
+		) {
 		clock = rcc_apb2_frequency;
 	}
 #endif