diff --git a/tools/codeblocks.py b/tools/codeblocks.py
index 7db82b49e9f5dc839da71db9bcc19bedae20d5fe..6bcca474c4b60ebbae7ec1e54d312c9c5d43af9f 100644
--- a/tools/codeblocks.py
+++ b/tools/codeblocks.py
@@ -108,7 +108,7 @@ def CBProject(target, script, program):
 
         for macro in building.Env.get('CPPDEFINES', []):
             Add = SubElement(elem, 'Add')
-            Add.set('option', "-D"+macro)
+            Add.set('option', "-D"+macro[0])
         
         # write link flags
     '''