diff --git a/src/stm32/serial.c b/src/stm32/serial.c
index b0cb1f55..9c3e7e84 100644
--- a/src/stm32/serial.c
+++ b/src/stm32/serial.c
@@ -25,7 +25,7 @@
   #define USARTx USART2
   #define USARTx_IRQn USART2_IRQn
 #elif CONFIG_SERIAL_PORT == 3
-  #if STM32_SERIAL_USART3_ALT
+  #if CONFIG_STM32_SERIAL_USART3_ALT
     DECL_CONSTANT_STR("RESERVE_PINS_serial", "PD9,PD8");
     #define GPIO_Rx GPIO('D', 9)
     #define GPIO_Tx GPIO('D', 8)
diff --git a/src/stm32/stm32f0_serial.c b/src/stm32/stm32f0_serial.c
index 452d66c9..2ea71f0c 100644
--- a/src/stm32/stm32f0_serial.c
+++ b/src/stm32/stm32f0_serial.c
@@ -19,7 +19,7 @@
   #define USARTx USART1
   #define USARTx_IRQn USART1_IRQn
 #elif CONFIG_SERIAL_PORT == 2
-  #if STM32_SERIAL_USART2_ALT
+  #if CONFIG_STM32_SERIAL_USART2_ALT
     DECL_CONSTANT_STR("RESERVE_PINS_serial", "PA15,PA14");
     #define GPIO_Rx GPIO('A', 15)
     #define GPIO_Tx GPIO('A', 14)