diff --git a/ironicclient/tests/unit/v1/test_node.py b/ironicclient/tests/unit/v1/test_node.py
index 7b8184d..352f11a 100644
--- a/ironicclient/tests/unit/v1/test_node.py
+++ b/ironicclient/tests/unit/v1/test_node.py
@@ -1221,7 +1221,7 @@ class NodeManagerTest(testtools.TestCase):
         self.mgr.inject_nmi(NODE1['uuid'])
         expect = [
             ('PUT', '/v1/nodes/%s/management/inject_nmi' % NODE1['uuid'],
-             {}, None),
+             {}, {}),
         ]
         self.assertEqual(expect, self.api.calls)
 
diff --git a/ironicclient/v1/node.py b/ironicclient/v1/node.py
index 5cf283d..8213f18 100644
--- a/ironicclient/v1/node.py
+++ b/ironicclient/v1/node.py
@@ -425,7 +425,7 @@ class NodeManager(base.CreateManager):
 
     def inject_nmi(self, node_uuid):
         path = "%s/management/inject_nmi" % node_uuid
-        return self.update(path, None, http_method='PUT')
+        return self.update(path, {}, http_method='PUT')
 
     def get_supported_boot_devices(self, node_uuid):
         path = "%s/management/boot_device/supported" % node_uuid