diff --git a/almalinux/gitutils/blob_upload.py b/almalinux/gitutils/blob_upload.py
index 50610ef..f378bd6 100644
--- a/almalinux/gitutils/blob_upload.py
+++ b/almalinux/gitutils/blob_upload.py
@@ -133,7 +133,7 @@ def main():
     iterator = get_file_iterator(args.file, args.input_metadata)
     out_fd = None
     if args.output_metadata:
-        out_fd = open(args.output_metadata, 'wa' if args.append_metadata else 'w')
+        out_fd = open(args.output_metadata, 'a' if args.append_metadata else 'w')
     try:
         for rel_path, checksum, checksum_type in iterator:
             file_path = normalize_path(rel_path)