diff --git a/src/file.c b/src/file.c
index f0e06e4..ed701a6 100644
--- a/src/file.c
+++ b/src/file.c
@@ -91,7 +91,7 @@ uint8_t openasmfiles (filearr_t *f, char *file)
     }
     replaceextension (file, ".obj");
 
-    f->obj = fopen (file, "w");
+    f->obj = fopen (file, "wb");
     if (f->obj == NULL) {
         notify ("Unable to open %s!\n", file);
         failed++;