diff --git a/tests/test_network_state.py b/tests/test_network_state.py
index 9fa381e..ee03c9b 100644
--- a/tests/test_network_state.py
+++ b/tests/test_network_state.py
@@ -234,7 +234,7 @@ async def write_parameter(param, *args):
                     command=None,
                 )
             },
-            {"network_key.tx_counter": 0},
+            {"network_key.tx_counter": 1073741824},
             {},
         ),
         (
diff --git a/zigpy_deconz/zigbee/application.py b/zigpy_deconz/zigbee/application.py
index ae9766e..c5a8a79 100644
--- a/zigpy_deconz/zigbee/application.py
+++ b/zigpy_deconz/zigbee/application.py
@@ -365,6 +365,11 @@ async def load_network_info(self, *, load_devices=False):
             )
         except zigpy_deconz.exception.CommandError as ex:
             assert ex.status == Status.UNSUPPORTED
+            LOGGER.debug(
+                "Conbee firmware is too old and does not support reading the frame"
+                " counter, picking a large value instead"
+            )
+            network_info.network_key.tx_counter = 2**30
 
         network_info.tc_link_key = zigpy.state.Key()
         network_info.tc_link_key.partner_ieee = await self._api.read_parameter(