diff --git a/radio/src/functions.cpp b/radio/src/functions.cpp
index 205964819..151206996 100644
--- a/radio/src/functions.cpp
+++ b/radio/src/functions.cpp
@@ -2,7 +2,7 @@
  * Copyright (C) OpenTX
  *
  * Based on code named
- *   th9x - http://code.google.com/p/th9x 
+ *   th9x - http://code.google.com/p/th9x
  *   er9x - http://code.google.com/p/er9x
  *   gruvin9x - http://code.google.com/p/gruvin9x
  *
@@ -286,7 +286,7 @@ void evalFunctions()
 
   for (uint8_t i=0; i<MAX_SPECIAL_FUNCTIONS; i++) {
     const CustomFunctionData * cfn = &functions[i];
-    int8_t swtch = CFN_SWITCH(cfn);
+    swsrc_t swtch = CFN_SWITCH(cfn);
     if (swtch) {
       MASK_CFN_TYPE switch_mask = ((MASK_CFN_TYPE)1 << i);