diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index f1e0733dda..109fb3884a 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -212,7 +212,7 @@ def get_virtio_scsi_device():
 
 class QemuIoInteractive:
     def __init__(self, *args):
-        self.args = qemu_io_args + list(args)
+        self.args = qemu_io_args_no_fmt + list(args)
         self._p = subprocess.Popen(self.args, stdin=subprocess.PIPE,
                                    stdout=subprocess.PIPE,
                                    stderr=subprocess.STDOUT,