diff --git a/arch/arm/src/a1x/a1x_serial.c b/arch/arm/src/a1x/a1x_serial.c
index 8865d792bf7..e17d11485cc 100644
--- a/arch/arm/src/a1x/a1x_serial.c
+++ b/arch/arm/src/a1x/a1x_serial.c
@@ -40,6 +40,7 @@
 #include <nuttx/config.h>
 
 #include <sys/types.h>
+#include <inttypes.h>
 #include <stdint.h>
 #include <stdbool.h>
 #include <unistd.h>
@@ -1130,7 +1131,7 @@ static int uart_interrupt(int irq, void *context, void *arg)
               /* Read the modem status register (MSR) to clear */
 
               status = up_serialin(priv, A1X_UART_MSR_OFFSET);
-              _info("MSR: %02x\n", status);
+              _info("MSR: %02" PRIx32 "\n", status);
               break;
             }
 
@@ -1141,7 +1142,7 @@ static int uart_interrupt(int irq, void *context, void *arg)
               /* Read the line status register (LSR) to clear */
 
               status = up_serialin(priv, A1X_UART_LSR_OFFSET);
-              _info("LSR: %02x\n", status);
+              _info("LSR: %02" PRIx32 "\n", status);
               break;
             }
 
@@ -1173,7 +1174,7 @@ static int uart_interrupt(int irq, void *context, void *arg)
 
           default:
             {
-              _err("ERROR: Unexpected IIR: %02x\n", status);
+              _err("ERROR: Unexpected IIR: %02" PRIx32 "\n", status);
               break;
             }
         }