diff --git a/run b/run
index bdf8986..6480bdb 100755
--- a/run
+++ b/run
@@ -433,7 +433,7 @@ Extra options to append at the end of the emulator command line.
             if self.env['kgdb']:
                 kernel_cli += ' kgdboc={},115200'.format(extra_console)
         if kernel_cli_after_dash:
-            kernel_cli += " -{}".format(kernel_cli_after_dash)
+            kernel_cli += " --{}".format(kernel_cli_after_dash)
         extra_env = {}
         if self.env['trace_insts_stdout']:
             if self.env['emulator'] == 'qemu':