diff --git a/builder/builder.ml b/builder/builder.ml
index 7d347b31c..af9c2f52d 100644
--- a/builder/builder.ml
+++ b/builder/builder.ml
@@ -618,7 +618,7 @@ let main () =
         (match iformat with
         | None -> ""
         | Some iformat -> sprintf " -f %s" (quote iformat))
-        (quote ifile) (quote oformat) (quote ofile)
+        (quote ifile) (quote oformat) (quote (qemu_input_filename ofile))
         (if verbose () then "" else " >/dev/null 2>&1") in
       if verbose () then printf "%s\n%!" cmd;
       if Sys.command cmd <> 0 then exit 1