iOS BLE cannot correctly read the model number.

[Leo Mo]

After updating from SDK V2.1.3 OTA to SDK V2.9.0, iOS cannot correctly read data such as the model number, but Android can read it normally.

Turn off Bluetooth in the system, turn it back on, and it can be read normally after connecting.

[Phyllis4]

Hi, I’m still pretty new to this, so sorry if this is a basic question 
Just to make sure I understand: you’re suggesting manually toggling Bluetooth off and on in iOS to clear the BLE service cache and then testing whether the device can reconnect and discover services correctly, right? If that does work, then the likely issue is that the Service Changed characteristic isn’t properly implemented in the app’s GATT services. Your reference link https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/samples/bluetooth/peripheral_ancs_client/README.html#peripheral-ancs-clientgeometry dash helps me a lot.

[Leo Mo]

Hi Einar,

Einar Thorsrud 

Any updates?

BR,

Leo

[Einar Thorsrud]

Hi Leo,

It seems like adding CONFIG_BT_GATT_ENFORCE_CHANGE_UNAWARE=y resolves the issue. Note that you also need to add the prototype for sc_restore_rsp() in gatt.c like this:

diff --git a/subsys/bluetooth/host/gatt.c b/subsys/bluetooth/host/gatt.c
index 70d6b289f41..02b5059bd08 100644
--- a/subsys/bluetooth/host/gatt.c
+++ b/subsys/bluetooth/host/gatt.c
@@ -264,6 +264,9 @@ BT_GATT_SERVICE_DEFINE(_2_gap_svc,
#endif
);
 
+static void sc_restore_rsp(struct bt_conn *conn,
+                          struct bt_gatt_indicate_params *params, uint8_t err);
+ 

We need to look a bit more into this, but the idea here is to prevent any notifications/indications from being sent before the service changed indication.