diff --git a/pylibfdt/libfdt.i b/pylibfdt/libfdt.i
index 3e09d3a..51ee801 100644
--- a/pylibfdt/libfdt.i
+++ b/pylibfdt/libfdt.i
@@ -1009,7 +1009,7 @@ typedef uint32_t fdt32_t;
 	}
 	$1 = (void *)PyByteArray_AsString($input);
         fdt = $1;
-        fdt = fdt; /* avoid unused variable warning */
+        (void)fdt; /* avoid unused variable warning */
 }
 
 /* Some functions do change the device tree, so use void * */
@@ -1020,7 +1020,7 @@ typedef uint32_t fdt32_t;
 	}
 	$1 = PyByteArray_AsString($input);
         fdt = $1;
-        fdt = fdt; /* avoid unused variable warning */
+        (void)fdt; /* avoid unused variable warning */
 }
 
 /* typemap used for fdt_get_property_by_offset() */