diff -dur deja-dup-34.2.orig/libdeja/BackendS3.vala deja-dup-34.2/libdeja/BackendS3.vala
--- deja-dup-34.2.orig/libdeja/BackendS3.vala	2014-04-29 03:42:09.000000000 +0200
+++ deja-dup-34.2/libdeja/BackendS3.vala	2016-09-19 18:21:32.140400704 +0200
@@ -41,6 +41,7 @@
   public override void add_argv(ToolJob.Mode mode, ref List<string> argv) {
     if (mode == ToolJob.Mode.INVALID)
       argv.append("--s3-use-new-style");
+    argv.append("--s3-use-multiprocessing");
   }
   
   string get_default_bucket() {