DFU not working

[bscdb]

Few issues I'm facing -

1. I have gone through the related blogs, tutorial, documentation for DFU. nRFConnect cannot connect to the Fanstel BM832 chip. It gives me an error BLE_HCI_CONN_FAILED_TO_BE_ESTABLISHED

2. Can another controller flash the application firmware to BLE chip over UART or does it still need the nrfutil?

3. Can nrfjprog.dll be used to flash code over BLE? Is nrfjprog.dll only used to flash code over UART or USB?

4. If I were to update application firmware over BLE, what are my options besides using nRFConnect & Nordic DK? How do I create my own tool to update the firmware?

5. What all changes are required to use NRF_BL_DFU_ENTER_METHOD_GPREGRET? Should I only enable it in sdk_config.h? Which is a simpler way to automate the process of entering DFU mode - NRF_BL_DFU_ENTER_METHOD_GPREGRET or NRF_BL_DFU_ENTER_METHOD_BUTTONLESS? Which examples should I use for buttonless DFU? Is the ble_app_buttonless_dfu used as application firmware?

6. Could you explain the purpose of 2 separate files - one says with bonds & other no bonds?

7. Where can I find a single or dual bank application update examples?

8. Dual bootloader - DFU (BLE) + UART

9. Does the DFU bootloader have a timeout?

10. How can I remove the dependency of nrf kit/dongle + nRFConnect + Mobile to flash firmware on BLE chip?

11. How is firmware.zip sent over BLE? Is it broken into packets?

12. Relation between WDT & DFU

[Hung Bui]

Hi Sonal, 

Please get familiar with the bootloader first. After you managed to do an DFU it will help answered many of your questions. 

Please go though my step by step guide here and let me know at which point you have an issue.

The guide you pointed to on git hub is an advanced guide for buttonless application. Please do a normal DFU first before testing with that guide. 

[bscdb]

https://devzone.nordicsemi.com/f/nordic-q-a/43357/qt-ble-firmware-upgrade/186156#186156 I came across this ticket which says that BLE DFU using Desktop makes use of nrf DK which is unavoidable. So my options are creating a mobile app based on Nordic DFU Library or custom transport layer. Am I right?

[Hung Bui]

Yes, it's possible. Please have a look at appendix 5 in this blog.

[bscdb]

1. How do I directly write the app firmware directly using Keil? Each time I edit app firmware, do I have to pack it in a .zip file, how do I debug the app code?

2. ble_app_buttonless_dfu code has problems connecting to the bluetooth. It pairs for hardly few seconds with my Windows machine & then disconnects. It works with nrfconnect but not my Windows machine.

Please guide on this.

[Hung Bui]

1. Since we have CRC checking you would need to create a new bootloader setting image for each image. But if you don't want to do that, you can edit the bootloader to avoid CRC checking. please look for app valid check in the bootloader

2. We would need to know why it disconnect. You may want to capture a sniffer trace. 

[bscdb]

I've attached the sniffer trace for you.

ble_app_buttonless.pcapng

I'm using the default example code, I did not make any changes.

8130.ble_app_buttonless_dfu.zip

[Hung Bui]

Which app do you run on Windows ? How do you plan to use it with native Windows Bluetooth ? 

From the sniffer trace what I can see is that Windows actively disconnect the connection, could be due to inactivity. My assumption is that Windows didn't see any Bluetooth SIG service and since there is no app requesting the connection, it will automatically disconnect the connection. 

[bscdb]

Ohh I was just checking the bluetooth connection first before checking it with my Windows app. But then how come the HID keyboard example holds the bluetooth connection? I was comparing all the files & found that ble_app_buttonless_dfu does not include code for whitelisting, peer manager is disabled & its a central. I tried to change it but had no effect. I found similar behaviour with ble_app_uart & ble_app_hrs. By the time I connect to bluetooth manually & open my Windows app, the connection is gone.

[Hung Bui]

HID keyboard is a special case. It's a keyboard. Windows automatically keep the connection and automatically reconnect if the device is in range. 

If you are doing other service, you would need an app on PC to connect.