Hi Marcel, I'm getting the following with latest bluetooth-testing kernel when accepting a connection when either device is in security mode 3: $ hcidump -V -r secmode3-acp.dump HCI sniffer - Bluetooth packet analyzer ver 1.42 btsnoop version: 1 datalink type: 1002 > HCI Event: Connect Request (0x04) plen 10 bdaddr 00:24:7D:XX:XX:XX class 0x5a020c type ACL < HCI Command: Accept Connection Request (0x01|0x0009) plen 7 bdaddr 00:24:7D:XX:XX:XX role 0x00 Role: Master > HCI Event: Command Status (0x0f) plen 4 Accept Connection Request (0x01|0x0009) status 0x00 ncmd 1 > HCI Event: Role Change (0x12) plen 8 status 0x00 bdaddr 00:24:7D:XX:XX:XX role 0x00 Role: Master > HCI Event: Link Key Request (0x17) plen 6 bdaddr 00:24:7D:XX:XX:XX < HCI Command: Link Key Request Negative Reply (0x01|0x000c) plen 6 bdaddr 00:24:7D:XX:XX:XX > HCI Event: Command Complete (0x0e) plen 10 Link Key Request Negative Reply (0x01|0x000c) ncmd 1 status 0x00 bdaddr 00:24:7D:XX:XX:XX > HCI Event: PIN Code Request (0x16) plen 6 bdaddr 00:24:7D:XX:XX:XX < HCI Command: Create Connection Cancel (0x01|0x0008) plen 6 bdaddr 00:24:7D:XX:XX:XX > HCI Event: Command Complete (0x0e) plen 10 Create Connection Cancel (0x01|0x0008) ncmd 1 status 0x00 bdaddr 00:24:7D:XX:XX:XX > HCI Event: Connect Complete (0x03) plen 11 status 0x02 handle 12 bdaddr 00:24:7D:XX:XX:XX type ACL encrypt 0x00 Error: Unknown Connection Identifier As you see, the kernel is sending "Create Connection Cancel" for this acceptor use case even though it's a connection initiator command. It comes immediately after the PIN code request when bluetoothd is waiting for the UI to respond. I'll try to find some time to investigate this during the weekend but decided to also post it here in case you know a simple fix for it. Johan -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html