mjhjmtu

I am trying to connect an Ubuntu 16.04 device running BlueZ 5.37 to a Body/Fat scale, and would love some help in trying to diagnose this issue. Here are some of the things I've tried:

• I can successfully connect to a number of other devices by the same manufacturer using the BlueZ stack on this device.


• I have connected to this scale successfully and without issue via both my Android phone and my Mac.


• I've attempted the connection to the scale via both my own application calling BlueZ as well as directly with bluetoothctl, and in both cases I get the same result.


• I am able to discover the scale during the scan, but any connection I initiate seems to fail without completing.

When I perform the scan, I can see the LE advertising report from the scale, and from its flags, it seems to indicate that pairing is not supported on this device (the ADV_IND returns 0x04 in the flags field, indicating that BR/EDR is not supported, so pairing support is not necessary on this device). Once BlueZ attempts the connection, it seems to initiate a pairing request, and the scale correctly indicates that the pairing failed because pairing is not supported. At this point BlueZ disconnects from the scale reporting an Authentication Failure. After a short period of time, the process will repeat itself, with it never making a request without requesting pairing.

Is there a flag I can enable somewhere in my client to indicate that I don't want pairing to occur?

Here's my hcidump of the failed connection attempt:

 HCI Event: Command Complete (0x0e) plen 4
 LE Set Random Address (0x08|0x0005) ncmd 1
 status 0x00
 HCI Event: Command Complete (0x0e) plen 4
 LE Set Scan Parameters (0x08|0x000b) ncmd 1
 status 0x00
 HCI Event: Command Complete (0x0e) plen 4
 LE Set Scan Parameters (0x08|0x000b) ncmd 1
 status 0x00
 HCI Event: Command Complete (0x0e) plen 4
 LE Set Scan Enable (0x08|0x000c) ncmd 1
 status 0x00
> HCI Event: LE Meta Event (0x3e) plen 37
 LE Advertising Report
 ADV_IND - Connectable undirected advertising (0)
 bdaddr DC:35:B8:04:C8:83 (Random)
 Flags: 0x04
 Shortened service classes: 0x181d
 Unknown type 0x06 with 16 bytes data
 RSSI: -67
 HCI Event: Command Complete (0x0e) plen 4
 LE Set Scan Enable (0x08|0x000c) ncmd 1
 status 0x00
 HCI Event: Command Status (0x0f) plen 4
 LE Create Connection (0x08|0x000d) status 0x00 ncmd 1
> HCI Event: LE Meta Event (0x3e) plen 19
 LE Connection Complete
 status 0x00 handle 64, role master
 bdaddr DC:35:B8:04:C8:83 (Random)
 HCI Event: Command Status (0x0f) plen 4
 LE Read Remote Used Features (0x08|0x0016) status 0x00 ncmd 1
> HCI Event: LE Meta Event (0x3e) plen 12
 LE Read Remote Used Features Complete
 status 0x00 handle 64
 Features: 0x01 0x00 0x00 0x00 0x00 0x00 0x00 0x00
 ACL data: handle 64 flags 0x02 dlen 7
 ATT: MTU resp (0x03)
 server rx mtu 23
> HCI Event: Number of Completed Packets (0x13) plen 5
 handle 64 packets 1
> ACL data: handle 64 flags 0x02 dlen 6
 SMP: Security Request (0x0b)
 auth req 0x01
 ACL data: handle 64 flags 0x02 dlen 6
 SMP: Pairing Failed (0x05)
 reason 0x05
 Reason Pairing Not Supported
 HCI Event: Command Status (0x0f) plen 4
 Disconnect (0x01|0x0006) status 0x00 ncmd 1
> HCI Event: Disconn Complete (0x05) plen 4
 status 0x00 handle 64 reason 0x13
 Reason: Remote User Terminated Connection
> HCI Event: Number of Completed Packets (0x13) plen 5
 handle 64 packets 1