diff --git a/src/Module.cpp b/src/Module.cpp
index db3b56f2..17e09480 100644
--- a/src/Module.cpp
+++ b/src/Module.cpp
@@ -5,8 +5,14 @@
 #include <stdio.h>
 #include <string.h>
 
+#if defined(RADIOLIB_DEBUG)
+// needed for debug print
+#include <stdarg.h>
+#endif
+
 #if defined(RADIOLIB_BUILD_ARDUINO)
 #include "ArduinoHal.h"
+
 Module::Module(uint32_t cs, uint32_t irq, uint32_t rst, uint32_t gpio) : csPin(cs), irqPin(irq), rstPin(rst), gpioPin(gpio) {
   this->hal = new ArduinoHal();
 }