diff --git a/stm-firmware/create-c-file-with-header.py b/stm-firmware/create-c-file-with-header.py
index 5ad8c48..af79b01 100755
--- a/stm-firmware/create-c-file-with-header.py
+++ b/stm-firmware/create-c-file-with-header.py
@@ -6,7 +6,7 @@ import pathlib
 
 license_header = """/* Reflow Oven Controller
 *
-* Copyright (C) 2020  Mario Hüttel <mario.huettel@gmx.net>
+* Copyright (C) 2022  Mario Hüttel <mario.huettel@gmx.net>
 *
 * This file is part of the Reflow Oven Controller Project.
 *
@@ -37,7 +37,7 @@ cpath = os.path.join(project_dir, sys.argv[1]+'.c')
 hfile = sys.argv[1]+'.h'
 hpath = os.path.join(module_include_dir, hfile)
 
-h_define = '__'+hfile.replace('.', '_').replace('-', '_').replace('/', '_').upper()+'__'
+h_define = '_'+hfile.replace('.', '_').replace('-', '_').replace('/', '_').upper()+'_'
 
 if os.path.exists(cpath) or os.path.exists(hpath):
 	print("File already exists! Abort!")