Environment:
iOS Version: 26.0 Device Model: iPhone 12 Pro Max Peripheral: [Fill in peripheral name/model/firmware version] Steps to Reproduce:
Connect to the peripheral using CoreBluetooth. Discover services via discoverServices. Discover characteristics via discoverCharacteristics. Call setNotifyValue:YES for a characteristic that supports notifications (Notify or Indicate). Capture the HCI log during the above process. Expected Result:
After calling setNotifyValue:YES, CoreBluetooth should write the appropriate value to the Client Characteristic Configuration descriptor (UUID: 0xFCF8) to enable notifications, and subsequent notifications should be received from the peripheral. Actual Result:
After calling setNotifyValue:YES, no subscription action is triggered.
HCI logs show that the subscription write to the CCC descriptor (0xFCF8) is missing. The target service and characteristic values have already been discovered prior to calling setNotifyValue:YES. Additional Information:
HCI log screenshot attached below highlights the moment after setNotifyValue:YES was invoked, showing no GATT Write Request to the CCC descriptor. Full HCI log file is also attached for reference.
11:29:38:165: Call setNotifyValue: YES