NRF52833: Impelementation of DFU serial bootloder without signed key.

[Swapnil Karkare]

Hi,

We have 2 microcontroller on board. One of our micro controller will update nordic chip using serial DFU without any signed keys.

For testing purpose i am implementing simple Serial bootloader On NRF52833 development kit and SDK 16.0.0. 

I am referring following example.

https://devzone.nordicsemi.com/f/nordic-q-a/56155/nrf52833-uart-bootloader

I am able to run example code on NRF52833 dev board but serial DFU is failing.

I am facing following issue:

1. I unable the  NRF_DFU_REQUIRE_SIGNED_APP_UPDATE 0 for not using secure bootloader. is this right to ignore signed dfu update?
2.  I have created zip package "nrfutil pkg generate --debug-mode --application ble_llecu4.hex app_dfu_serial_pkg.zip" for testing purpose. is this right?
3. Using zip file i have tried to transfer application file "nrfutil dfu serial -pkg app_dfu_serial_pkg.zip -p 5 -b 115200 -fc 0" but iam getting following error

File "c:\python38-32\lib\site-packages\nordicsemi\dfu\dfu_transport_serial.py", line 202, in open
raise NordicSemiException("Serial port could not be opened on {0}"
pc_ble_driver_py.exceptions.NordicSemiException: Serial port could not be opened on 5. Reason: None

 

Can anybody suggest above approach is right or not? Also what will be the while accessing serial port.

[Simonr]

Hi Swapnil

This should be possible, but we don't have anything that does this already, so you will have to implement this yourself. Here are a few suggestions for what you can take a look at. Please check out the message sequence chart here which describes how the transfer of an init packet and firmware image is done. 

You can also modify the UART DFU Master code, found here, to use the BLE transportation layer instead of UART.

Best regards,

Simon