Bluetooth-LE severe failure after the latest OS update in Galaxy Watch

I’m a developer of an app for Wear OS which utilizes Bluetooth-LE. Since the latest Wear OS update (Wear OS 4.0, One UI 5.0), it started failing for numerous users of mine with Samsung Galaxy Watch 5 models.

I have managed to verify the failure myself. I have also created another minimal app which just attempts to establish a simple Gatt LE connection, which also fails.

Both apps run successfully on Galaxy Watch 4, Google Pixel Watch, and other models, but fail on Galaxy Watch 5 models. All running the same software: Wear OS 4.0 and One UI 5.0.

I have detailed logs, bluetooth manager dump/events and bluetooth snoop logs with details about the failure, but briefly:

My app tries to establish a Gatt connection with bluetoothDevice.connectGatt(context, false, gattCallback, BluetoothDevice.TRANSPORT_LE), but the BluetoothGattCallback is never called.

The bt_stack ( logs show a few key details:

At first, it starts fairly normal:

W Creating le direct connection to:xx:xx:xx:xx:03:1f[public]
W AcceptLeConnectionFrom xx:xx:xx:xx:03:1f
W Allow Le connection from remote:xx:xx:xx:xx:03:1f[PUBLIC_DEVICE_ADDRESS]
W create_le_connection :: address : a8:22:9f, add_to_connect_list : 1, is_direct : 1
W add_device_to_connect_list a8:22:9f :: Send command after register

But at some point, it mentions a weird nil address and fails with CONNECTION_ALREADY_EXISTS:

W No prior connection request for 00:00:00
W Device not in acceptlist and cannot be removed:00:00[PUBLIC_DEVICE_ADDRESS]
W le_impl::add() handle=0x42 addr=00:00:00
W create_le_connection :: address : 00:00:00, add_to_connect_list : 0, is_direct : 0
W add_to_connect_list is false. call arm_connectability()
W Unknown device being removed from acceptlist:xx:xx:xx:xx:00:00[PUBLIC_DEVICE_ADDRESS]
W arm_connectability()
W on_le_disconnect Handle : 0x42, Reason : 62
W le_impl::remove() handle=0x42 addr=00:00:00
W [Current Device list in background_connections_ set]
E Unable to find sco connection
W Got uncommon disconnection reason:Connection Failed Establishment handle:0x0042 comment:stack::acl::btm_acl::btm_acl_disconnected
W Got disconnect for unknown device record handle:0x0042

I have tried whatever I can to run around it, but couldn’t find a way. I’m quite certain this is a bug in Wear OS or some driver related to Galaxy Watch 5. The nil address might even hint at some memory corruption which might potentially be a security vulnerability.

Could you help me get it to the right people? Thank you.

As the issue is restricted to Samsung, you can report this to Samsung Developer Support directly for proper analysis.


Any updates about this issue?