Soft device enable and disable - [DFU] disconnected by the remote device

[AliMahmood123]

Hello all

I am facing a very strange issue, already searched the forum but didnt find anything like it.

Okay so I can get DFU to work. For our custom application we have to disable the soft device for some time for sensor acquisitions and re enable it at a later time for OTA upgrades.

I simply use nrf_sdh_disable_request() to de initialize the soft device successfully, which it does.

I later re - enable soft device using the standard ble calls in example code:

ble_stack_init();
    peer_manager_init();
    gap_params_init();
    gatt_init();
    advertising_init();
    services_init_2();
    conn_params_init();   
     
    //Start execution.
    application_timers_start();
    advertising_start(erase_bonds);

BLE gets initialized successfully, device is advertised and connects to as well. The problem is in DFU. When I attempt DFU, it keeps getting stuck into trying to switch to bootloader, repeatedly giving
"[DFU] disconnected by the remote device"

The logs then try to open the firmware file again, re initiating the process but nothing happen. I have spend quite some time on this and hit a blocker. Any help is appreciated. There must be a step I am missing during re-enabling the soft device

[Vidar Berg]

Hello,

"[DFU] disconnected by the remote device"

Where is this message printed? Is it in the mobile app on iOS or Android? And have you tried to debug the FW app to see if it hangs or enters the app_error_fault_handler() function?

Okay so I can get DFU to work. For our custom application we have to disable the soft device for some time for sensor acquisitions and re enable it at a later time for OTA upgrades.

Sure you really need to disable the Softdevice for this? The only case I can think of where it makes sense to disable the Softdevice is when there is a need to stop the LF clock. 

Best regards,

Vidar

[AliMahmood123]

Hi Vidar.
I read an article here which said that in order to disable a service and re-enable it later, I need to disable the whole soft device as the services at start up become part of the "stack"

if there is another way, please let me know. Basically I just want to disable the DFU service and show that service at some other point

Also, this message appeared on the android app

[AliMahmood123]

Okay so I have another finding related to this. When I simply Build & Run the example Bootloader project, it works. Shifting it to detect bonds does not work, it keeps restarting when trying to enabling BLE : app: Received an error: 0x00000003!

Okay so that's kinda obvious I think.

However, is this the same reason I am unable to debug a project with bonded bootloader, and it is unable to go past ble_dfu_buttonless_async_svci_init()? Am I to do something while generating the settings?

Moreover, By changing my main app project to without bonding, as well as non bonded bootloader, I am able to debug the application successfully, even without doing NO_VALIDATION on the settings page

So I am thinking it's got something to do with bonds

[Vidar Berg]

The CPU starts execution directly from the application's Reset_Handler when you use "Build & run", effectively bypassing the Softdevice and Bootloader. So please use "Build and Debug" instead. This will follow the project configuration and use address 0x0 as the entry point.

AliMahmood123 said:

However, is this the same reason I am unable to debug a project with bonded bootloader, and it is unable to go past ble_dfu_buttonless_async_svci_init()? Am I to do something while generating the settings?

Where does it hang? Can you post a screenshot showing the call stack and cpu registers?

[AliMahmood123]

Alongside this:

[Vidar Berg]

Hi,

I'm not sure if I have seen this error before. It's as if the debugger loses connection to the target. I was not able to replicate this here either. I programmed the bootloader, softdevice, buttonless template app and the settings page (with bonds enabled), and then stepped through the ble_dfu_buttonless_async_svci_init() function in main.

Are you able to reproduce this with the original projects?

[AliMahmood123]

Yes I reproduced it with the original project as well. What do you think could be the issue then? I have also tried multiple Dev boards here.

and the settings page (with bonds enabled),

Is there a different BL settings page for bond enabled?

[Vidar Berg]

Just to confirm, you were able to reproduce this with the original unmodified SDK example as well (i.e. unmodified except for the bond configuration setting)? What SDK version do you use?

[AliMahmood123]

Hi Vidar. Our custom project was in debug mode, and the bootloader project is always in Release Mode. So both need to be in Release mode.

Although I don't know why that is necessary. Thanks a lot for all your help and patience :)

[Vidar Berg]

Hi,

Thanks for the update. However, it should not be necessary to align the build configuration between the bootloader and app. The difference between release and debug in our projects is that debug disables code optimization and enables the DEBUG and DEBUG_NRF flag as you can see here:

  <configuration Name="Release"
    c_preprocessor_definitions="NDEBUG"
    link_time_optimization="No"    gcc_optimization_level="Optimize For Size" />
  <configuration Name="Debug"
    c_preprocessor_definitions="DEBUG; DEBUG_NRF"
    gcc_optimization_level="None"/>

Maybe your debug jlink settings file is corrupted. You can try to delete the *.jlink setting files in your project directory. SES will create a new setting file next time you start a debug session.

[AliMahmood123]

Hmm I will look into this and try this. Thanks a lot

Also, once again, I have another question

Actually I keep assuming it's better than posting in a new thread and this is easier for the nordic team, but I am not sure.

So the question is that I was looking into Single vs Dual Bank

I play with NRF_DFU_FORCE_DUAL_BANK_APP_UPDATES and NRF_DFU_SINGLE_BANK_APP_UPDATES. In single bank mode I stop DFU in between and on restart I always see DFU Mode

For Double bank I always get the old application on re-start
My question is that is it possible for the bootloader to simply re-start the system if interrupted on DFU? Because we cant restart the devices in the field in case of a failed DFU. Even if we can, we dont want to. Is it possible to add that in the bootloader project using NVIC Reset?

[Vidar Berg]

Ideally we want there to be one question and one correct answer per thread. Long threads are hard to follow for others who may be looking for the same answers.

Anyway. I'm not sure I understand your last question. Do you want the bootloader to fall back to DFU mode or boot the main app after a failed DFU attempt? The bootloader has an inactivity timer that expires after 2 minutes by default So the bootloader will not get stuck in DFU mode if you still have the old app in bank 0.