diff --git a/contrib/win32/libnfc/buses/uart.c b/contrib/win32/libnfc/buses/uart.c
index 1cc2043..695c048 100644
--- a/contrib/win32/libnfc/buses/uart.c
+++ b/contrib/win32/libnfc/buses/uart.c
@@ -176,7 +176,7 @@ uart_receive(serial_port sp, uint8_t *pbtRx, const size_t szRx, void *abort_p, i
   timeouts.WriteTotalTimeoutConstant = timeout_ms;
 
   if (!SetCommTimeouts(((struct serial_port_windows *) sp)->hPort, &timeouts)) {
-    log_put(LOG_GROUP, LOG_CATEGORY, NFC_LOG_PRIORITY_ERROR, "Unable to apply new timeout settings.");
+    log_put(LOG_GROUP, LOG_CATEGORY, NFC_LOG_PRIORITY_ERROR, "%s", "Unable to apply new timeout settings.");
     return NFC_EIO;
   }
   log_put(LOG_GROUP, LOG_CATEGORY, NFC_LOG_PRIORITY_DEBUG, "Timeouts are set to %lu ms", timeout_ms);
@@ -185,7 +185,7 @@ uart_receive(serial_port sp, uint8_t *pbtRx, const size_t szRx, void *abort_p, i
   // - According to MSDN, it could be better to implement nfc_abort_command() mecanism using Cancello()
   volatile bool *abort_flag_p = (volatile bool *)abort_p;
   do {
-    log_put(LOG_GROUP, LOG_CATEGORY, NFC_LOG_PRIORITY_DEBUG, "ReadFile");
+    log_put(LOG_GROUP, LOG_CATEGORY, NFC_LOG_PRIORITY_DEBUG, "%s", "ReadFile");
     res = ReadFile(((struct serial_port_windows *) sp)->hPort, pbtRx + dwTotalBytesReceived,
                    dwBytesToGet,
                    &dwBytesReceived, NULL);
@@ -226,7 +226,7 @@ uart_send(serial_port sp, const uint8_t *pbtTx, const size_t szTx, int timeout)
   timeouts.WriteTotalTimeoutConstant = timeout;
 
   if (!SetCommTimeouts(((struct serial_port_windows *) sp)->hPort, &timeouts)) {
-    log_put(LOG_GROUP, LOG_CATEGORY, NFC_LOG_PRIORITY_ERROR, "Unable to apply new timeout settings.");
+    log_put(LOG_GROUP, LOG_CATEGORY, NFC_LOG_PRIORITY_ERROR, "%s", "Unable to apply new timeout settings.");
     return NFC_EIO;
   }
 
diff --git a/libnfc/drivers/acr122s.c b/libnfc/drivers/acr122s.c
index 55a57c3..0ee49fd 100644
--- a/libnfc/drivers/acr122s.c
+++ b/libnfc/drivers/acr122s.c
@@ -198,11 +198,12 @@ acr122s_send_frame(nfc_device *pnd, uint8_t *frame, int timeout)
   uint8_t positive_ack[4] = { STX, 0, 0, ETX };
   serial_port port = DRIVER_DATA(pnd)->port;
   int ret;
-  void *abort_p;
 
 #ifndef WIN32
+  void *abort_p;
   abort_p = &(DRIVER_DATA(pnd)->abort_fds[1]);
 #else
+  volatile void *abort_p;
   abort_p = &(DRIVER_DATA(pnd)->abort_flag);
 #endif