cannot convert 'NoneType' object to bytearray while flashing with nrfutil

[Tamizh]

Hi, devzone,

I'm currently trying to flash the nrf52840 dongle from a custom IMX6-Ull board where it is attached and I'm also able to communicate and run the application flashed in the dongle. 

I want to integrate the nrfutil tool into the board for firmware upgrade purposes and get the following error while running the dfu usb-serial command.

> nrfutil dfu usb-serial -pkg zephyr.zip -p /dev/ttymxc6

This is the error I'm getting as a response TypeError: cannot convert 'NoneType' object to byte array

  [------------------------------------]    0%
Traceback (most recent call last):
  File "/usr/bin/nrfutil", line 33, in <module>
    sys.exit(load_entry_point('nrfutil==6.1.7', 'console_scripts', 'nrfutil')())
  File "/usr/lib/python3.8/site-packages/click/core.py", line 1130, in __call__
    return self.main(*args, **kwargs)
  File "/usr/lib/python3.8/site-packages/click/core.py", line 1055, in main
    rv = self.invoke(ctx)
  File "/usr/lib/python3.8/site-packages/click/core.py", line 1657, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/lib/python3.8/site-packages/click/core.py", line 1657, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/lib/python3.8/site-packages/click/core.py", line 1404, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/lib/python3.8/site-packages/click/core.py", line 760, in invoke
    return __callback(*args, **kwargs)
  File "/usr/lib/python3.8/site-packages/nordicsemi/__main__.py", line 1032, in usb_serial
    do_serial(package, port, connect_delay, flow_control, packet_receipt_notification, baud_rate, serial_number, False,
  File "/usr/lib/python3.8/site-packages/nordicsemi/__main__.py", line 988, in do_serial
    dfu.dfu_send_images()
  File "/usr/lib/python3.8/site-packages/nordicsemi/dfu/dfu.py", line 127, in dfu_send_images
    self._dfu_send_image(self.manifest.application)
  File "/usr/lib/python3.8/site-packages/nordicsemi/dfu/dfu.py", line 88, in _dfu_send_image
    self.dfu_transport.open()
  File "/usr/lib/python3.8/site-packages/nordicsemi/dfu/dfu_transport_serial.py", line 217, in open
    self.__get_mtu()
  File "/usr/lib/python3.8/site-packages/nordicsemi/dfu/dfu_transport_serial.py", line 366, in __get_mtu
    self.mtu = struct.unpack('<H', bytearray(response))[0]
TypeError: cannot convert 'NoneType' object to bytearray

While trying through the USB interface(ttyACM0) from the PC I'm able to flash the firmware successfully

Any suggestions? 

Thank you in advance

[Vidar Berg]

Hi,

The Python traceback shows that the script fails because it does not receive anything in response from the DFU target after it sends the MTU Get request. But I am not sure why this would happen. Would it be possible to run the Command Line Interface (CLI) Example on your dongle and connect it to your IMX6-Ull to verify if the USB communication is working? 

Best regards,

Vidar

[Tamizh]

Hi Vidar Berg ,

Thanks for the reply.

In the dongle, I've already flashed the rcp coprocessor open-thread application program which gives a CLI for interaction called ot-ctl.

I'm able to send commands and get the firmware version and other information from the dongle through uart

so I think the connection is fine through /dev/ttymxc6.

[Tamizh]

Hi,

Yes the dfu mode is enabled and the red LED is blinking but not sure why it's still unable to communicate. Is there any config need to be enabled (by JLINK) for flashing through the serial port(ttymxc6)?

[Vidar Berg]

Hi,

Thank you for confirming.

There is no JLink involved in this case (the nrf52840 dongle does not have an on-board Jlink like the devkits). ttymxc6 should communicate directly with the nRF52840 USB (CDC) on the dongle. What I do not understand is why you have TX/RX communication when running the OT CLI, but not when running the bootloader.

I do not have experience with these NXP boards, and I am unsure what troubleshooting step to suggest next. Maybe you can try to enable flow control to see if it makes any difference? 

[Tamizh]

Hi Vidar Berg ,

Sorry for the delay. I've tried the above method also, but still, it is not working.

I'll be receiving the custom board from my team with integrated nrf52840 SoC. I'll try the same on the board and update the result here.

But if you have any other ideas for the dongle dfu, please suggest that also. 

Thanks.

[Vidar Berg]

Hi,

Tamizh said:

I'll be receiving the custom board from my team with integrated nrf52840 SoC.

Will the 52840 be connected to the host MCU via USB or UART in this case?

[Tamizh]

via UART

[Vidar Berg]

I see. Hopefully the IMX6 will be able to communicate with the nRF52840 when you use UART instead of the USB interface. Let me know if it doesn't.