diff --git a/esp3d/src/core/debug_esp3d.cpp b/esp3d/src/core/debug_esp3d.cpp
index bf4d52d6..399edcb6 100644
--- a/esp3d/src/core/debug_esp3d.cpp
+++ b/esp3d/src/core/debug_esp3d.cpp
@@ -23,7 +23,7 @@
 
 #ifndef DEBUG_BAUDRATE
 #define DEBUG_BAUDRATE 115200
-#ndif //~DEBUG_BAUDRATE
+#endif //~DEBUG_BAUDRATE
 
 #if defined(ARDUINO_ARCH_ESP8266)
 const char * pathToFileName(const char * path)
diff --git a/esp3d/src/modules/serial/serial_service.cpp b/esp3d/src/modules/serial/serial_service.cpp
index e3d7c010..3c636f65 100644
--- a/esp3d/src/modules/serial/serial_service.cpp
+++ b/esp3d/src/modules/serial/serial_service.cpp
@@ -287,7 +287,7 @@ size_t SerialService::write(const uint8_t *buffer, size_t size)
     }
 }
 
-uint SerialService::availableForWrite()
+int SerialService::availableForWrite()
 {
     return ESP3D_SERIAL.availableForWrite();
 }
diff --git a/esp3d/src/modules/serial/serial_service.h b/esp3d/src/modules/serial/serial_service.h
index cfcecb4b..6f91ca3c 100644
--- a/esp3d/src/modules/serial/serial_service.h
+++ b/esp3d/src/modules/serial/serial_service.h
@@ -39,7 +39,7 @@ public:
     const long * get_baudratelist(uint8_t * count);
     void flush();
     void swap();
-    uint availableForWrite();
+    int availableForWrite();
     int available();
     bool is_valid_baudrate(long br);
     size_t write(uint8_t c);