diff --git a/src/i_nucleo_lrwan1_wm_sg_sm_xx.c b/src/i_nucleo_lrwan1_wm_sg_sm_xx.c
index 988edd6..00a7892 100644
--- a/src/i_nucleo_lrwan1_wm_sg_sm_xx.c
+++ b/src/i_nucleo_lrwan1_wm_sg_sm_xx.c
@@ -578,7 +578,7 @@ static ATEerror_t at_cmd_receive_async_event_downlink_data(void *pdata)
   int8_t i = 0;
   int8_t charnumber = 0;
   char *ptrChr;
-  ATEerror_t RetCode;
+  ATEerror_t RetCode = AT_OK;
   /* Discriminate the Get return code from return value */
   uint8_t NoReturnCode =1;
   int8_t DlinkData_Complete = (0x1U);
diff --git a/src/tiny_vsnprintf.c b/src/tiny_vsnprintf.c
index 70976f9..18e638a 100644
--- a/src/tiny_vsnprintf.c
+++ b/src/tiny_vsnprintf.c
@@ -681,6 +681,7 @@ int tiny_vsnprintf_like(char *buf, const int size, const char *fmt, va_list args
 
       case 'X':
         flags |= UPPERCASE;
+        __attribute__ ((fallthrough));
 
       case 'x':
         base = 16;