diff --git a/src/osmo_gsm_tester/ms_osmo_mobile.py b/src/osmo_gsm_tester/ms_osmo_mobile.py
index 1c28117..f497772 100644
--- a/src/osmo_gsm_tester/ms_osmo_mobile.py
+++ b/src/osmo_gsm_tester/ms_osmo_mobile.py
@@ -26,3 +26,9 @@
     def cleanup(self):
         # do nothing for a virtual resource
         pass
+
+    def ki(self):
+        ki = super().ki()
+        if not ki:
+            return "00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00"
+        return ki