diff --git a/run b/run
index 852937d..dae9ad0 100755
--- a/run
+++ b/run
@@ -790,8 +790,8 @@ Extra options to append at the end of the emulator command line.
                 '-cpu', cpu, LF,
             ])
         if self.env['tmux']:
-            tmux_args = "--gem5-worktree '{}' --run-id {}".format(
-                self.env['gem5_worktree'],
+            tmux_args = "--gem5-build-id '{}' --run-id {}".format(
+                self.env['gem5_build_id'],
                 self.env['run_id']
             )
             if self.env['tmux_program'] == 'shell':