Android Device Fails to Reconnect after Firmware Update with Preserved APP data

RE: Android Device Fails to Reconnect after Firmware Update with Preserved APP data

bjorn-spockeli — Tue, 12 May 2020 14:05:22 GMT

Ah, I was not aware that the Android DFU Library would delete the bonding information by default. Happy to hear that you found the cause of the issue.

Best regards

Bjørn

RE: Android Device Fails to Reconnect after Firmware Update with Preserved APP data

yaoCheng — Tue, 12 May 2020 13:23:19 GMT

Hi bjorn,

the problem is now solved.

The Android App uses the standard NORDIC library and the bonding information is deleted by default.

That is why it no longer knows my device.

thank you very much for your support 🙂

best regards,

Yao

RE: Android Device Fails to Reconnect after Firmware Update with Preserved APP data

yaoCheng — Mon, 11 May 2020 15:30:02 GMT

Hi bjorn,

yes, the APP data is preserved by changing DFU_APP_DATA_RESERVED.

My Device reconnectes successfully to an IOS device after FW update, without a new pairing. So I am sure that the bonding information is still there after update. The problem only exists with Android device.

best regards,

Yao

RE: Android Device Fails to Reconnect after Firmware Update with Preserved APP data

bjorn-spockeli — Mon, 11 May 2020 13:25:57 GMT

Hi Yao,

have you configured the bootloader to preserve the application data, which also contains the bonding information, by setting DFU_APP_DATA_RESERVED to 0x0C00 , see Preserving application data.

Best regards

Bjørn

RE: Android Device Fails to Reconnect after Firmware Update with Preserved APP data

yaoCheng — Wed, 06 May 2020 08:20:26 GMT

@bjorn-spockeli

Hi Bjorn,

I still can not figure out what caused the problem...

do you have any idea about the difference between the following situations:

1. when my device normally starts, it goes into bootloader first, and then jumps into application

2. after FW update, my device jumps from bootloader to application.

Under the first condition, the Aondroid device does not try to rebond (it correctly recognizes my device as a "known device"), but under the second condition, the Aondroid device sends a bonding-request. Does the NORDIC SDK do anything different under these two situations?

Can the service changed characteristic cause the Android device to believe that my device is a new device?

best regards,

Yao

RE: Android Device Fails to Reconnect after Firmware Update with Preserved APP data

yaoCheng — Tue, 24 Mar 2020 14:21:59 GMT

Hi Bjørn,

the address shown by nRF sniffer is the same before and after firmware update.

I also tried to change the input argument of sec_status to BLE_GAP_SEC_STATUS_UNSPECIFIED, but my device and the Android mobile still fail to communicate with each other after firmware update.

Here is the communication captured by nRF sniffer (pairing request from already bonded device rejected),

devzone.nordicsemi.com/.../fw_5F00_update_5F00_then_5F00_reject_5F00_bond_5F00_info_5F00_refresh.pcapng

which shows the process of bonding, firmware update and then the failed trial to reconnect.

I think the request of pairing is rejected as you said (nRF sniffer No. 9688) . But I do not know why they still can not communicate with each other.

Yet I find something that looks strange to me without the modification mentioned above. Here is the communication captured by nRF sniffer (pairing request from already bonded device accepted):

devzone.nordicsemi.com/.../fw_5F00_update_5F00_then_5F00_accept_5F00_bond_5F00_info_5F00_refresh.pcapng

After the firmware update and the new pairing process, the master keeps on sending the packet LL_START_ENC_RSP(from nRF sniffer No 9982). Does this mean that there is something wrong with the APP?

best regards,

Yao

RE: Android Device Fails to Reconnect after Firmware Update with Preserved APP data

bjorn-spockeli — Tue, 24 Mar 2020 11:23:14 GMT

Hi Yao,

the sniffer trace confirms that its the Master, i.e. Android device that issues the Pairing request ( Packet No 1245) to which the Slave, i.e. the nRF51422, responds with a Pairing response. Then the Pairing confirm and pairing random values are exchanged and the encryption process is started.

The Device Manager allows the bond information to be refreshed so this is why it accepts the Pairing request.

I do not have any explanation for why the Android sends a the Pairing Request, but you could modify the DM source to reject a pairing request if you are already bonded and see if the Android device then tries to re-encrypt the link with the stored keys. You can do this by modifying the case BLE_GAP_EVT_SEC_PARAMS_REQUEST in dm_ble_evt_handler() in device_manager_peripheral.c to call sd_ble_gap_sec_params_reply() with sec_status== BLE_GAP_SEC_STATUS_UNSPECIFIED

Does the nRF51 device have the same Link Layer address, i.e. fb:9e:df:ab:fe:6f, before and after the DFU?

Best regards

Bjørn

RE: Android Device Fails to Reconnect after Firmware Update with Preserved APP data

yaoCheng — Mon, 23 Mar 2020 13:33:08 GMT

Hi Bjørn,

thanks for your reply.

I am using S110, v8.0.0.

The communication between my board and the Android mobile is captured by nRF sniffer, filtered by packet length non-zero (please refer to the following file):

devzone.nordicsemi.com/.../reconnect_5F00_with_5F00_android_5F00_after_5F00_fw_5F00_update.pcapng

After the FW update, when I try to reconnect to the Android mobile, I do receive the BLE_GAP_EVT_SEC_INFO_REQUEST event. The arguments passed to sd_ble_gap_sec_info_reply() are listed below:

conn_handle: 0x0000

*p_enc_info:

*p_id_info:

*p_sign_info: NULL

best regards,

Yao

RE: Android Device Fails to Reconnect after Firmware Update with Preserved APP data

bjorn-spockeli — Fri, 20 Mar 2020 11:18:37 GMT

Hi Yao,

could you capture a on-air trace of the communication between the nRF51822 and the Android device using our nRF Sniffer plugin in Wireshark and a NRF52 or NRF51 DK?

Which SoftDevice are you using on the nRF51422?

Do you receive the BLE_GAP_EVT_SEC_INFO_REQUEST event when you try to re-connect after the DFU, see the Peripheral Encryption Establishment using stored keys Message sequence chart? If so, then please debug the application and see what arguments the application is passing to sd_ble_gap_sec_info_reply() in device_manager_peripheral.c

Best regards

Bjørn