diff --git a/arch/arm/src/common/up_internal.h b/arch/arm/src/common/up_internal.h
index bd60b0fad1..929353e8c1 100644
--- a/arch/arm/src/common/up_internal.h
+++ b/arch/arm/src/common/up_internal.h
@@ -422,13 +422,13 @@ void up_lowputc(char ch);
 void up_puts(const char *str);
 void up_lowputs(const char *str);
 
-#if USE_SERIALDRIVER
+#ifdef USE_SERIALDRIVER
 void up_serialinit(void);
 #else
 #  define up_serialinit()
 #endif
 
-#if USE_EARLYSERIALINIT
+#ifdef USE_EARLYSERIALINIT
 void up_earlyserialinit(void);
 #else
 #  define up_earlyserialinit()
diff --git a/arch/arm/src/sam34/sam_serial.c b/arch/arm/src/sam34/sam_serial.c
index 745fada339..6aec44070a 100644
--- a/arch/arm/src/sam34/sam_serial.c
+++ b/arch/arm/src/sam34/sam_serial.c
@@ -1154,6 +1154,7 @@ static bool up_txempty(struct uart_dev_s *dev)
  *
  ****************************************************************************/
 
+#ifdef USE_EARLYSERIALINIT
 void up_earlyserialinit(void)
 {
   /* NOTE:  All GPIO configuration for the USARTs was performed in
@@ -1186,6 +1187,7 @@ void up_earlyserialinit(void)
   up_setup(&CONSOLE_DEV);
 #endif
 }
+#endif
 
 /****************************************************************************
  * Name: up_serialinit