Secure Serial DFU not working

[Rok Cesnovar]

I am using the bootloader_secure_serial example from the SDK 14.0.0 on a 523832 DK. I have erased the device and flashed the softdevice and bootlader on it. The LED1 is turned on after restart, so the bootloader is in DFU mode.  

I am having trouble testing the example with the nrfutil. I installed it using pip and tried running the command

nrfutil dfu serial -pkg name.zip - /dev/ttyUSB0 -b 115200 -fc 1

I get the "No ping response after opening COM port". Its not a problem with the UART or USB2UART module, as the ble_app_uart example is working fine on the same setup.

[Einar Thorsrud]

Hi,

Which exact OS do you use? Do you also have a /dev/ttyACMx device that represent the serial port?

[Anantha Keshava]

I'm facing a similar issue. Here are the steps followed by me:

Environment:

Dev OS: Linux 18.04 LTS

SDK version 15.0.0

Target: nRF52840-Preview DK

1. I erased the flash: $ nrfjprog -f NRF52 --recover
2. I flashed the softdevice: $ nrfjprog --program ~/workspace/src/SDK/components/softdevice/s140/hex/s140_nrf52_6.0.0_softdevice.hex --sectorerase --log
3. I flashed the bootloader settings: $ nrfjprog -f nrf52 --program bl_settings.hex --sectorerase --log --reset
4. I flashed the secure bootloader uart example: $ nrfjprog -f nrf52 --program _build/nrf52840_xxaa_mbr.hex --sectoranduicrerase --log --reset
   Please note that in this step, only changes made by me are:
   1. Changed the dfu keys
   2. increased the serial baud rate to 1M in ~/workspace/src/SDK/examples/dfu/secure_bootloader/pca10056_uart/config/sdk_config.h
   3. This should technically work as the uart example worked with flow control kept ON
5. I create a sample package based on ble_app_hrs_freertos with nrfutil and try to update this with the DFU serial using the command: $ sudo nrfutil dfu serial -pkg build/ble_app_freertos_gcc_nrf52.zip -p /dev/ttyACM0 -b 1000000

   [------------------------------------] 0%

   <Hang here>^C

   Aborted!
   $ sudo nrfutil dfu serial -pkg build/ble_app_freertos_gcc_nrf52.zip -p /dev/ttyACM0 -b 1000000 -fc 1
   [------------------------------------] 0%
   Traceback (most recent call last):
   File "/usr/local/bin/nrfutil", line 11, in <module>
   load_entry_point('nrfutil==3.5.1', 'console_scripts', 'nrfutil')()
   File "/home/akeshava/.local/lib/python2.7/site-packages/click/core.py", line 722, in __call__
   return self.main(*args, **kwargs)
   File "/home/akeshava/.local/lib/python2.7/site-packages/click/core.py", line 697, in main
   rv = self.invoke(ctx)
   File "/home/akeshava/.local/lib/python2.7/site-packages/click/core.py", line 1066, in invoke
   return _process_result(sub_ctx.command.invoke(sub_ctx))
   File "/home/akeshava/.local/lib/python2.7/site-packages/click/core.py", line 1066, in invoke
   return _process_result(sub_ctx.command.invoke(sub_ctx))
   File "/home/akeshava/.local/lib/python2.7/site-packages/click/core.py", line 895, in invoke
   return ctx.invoke(self.callback, **ctx.params)
   File "/home/akeshava/.local/lib/python2.7/site-packages/click/core.py", line 535, in invoke
   return callback(*args, **kwargs)
   File "/home/akeshava/.local/lib/python2.7/site-packages/nordicsemi/__main__.py", line 745, in serial
   do_serial(package, port, connect_delay, flow_control, packet_receipt_notification, baud_rate, True)
   File "/home/akeshava/.local/lib/python2.7/site-packages/nordicsemi/__main__.py", line 680, in do_serial
   dfu.dfu_send_images()
   File "/home/akeshava/.local/lib/python2.7/site-packages/nordicsemi/dfu/dfu.py", line 129, in dfu_send_images
   self._dfu_send_image(self.manifest.application)
   File "/home/akeshava/.local/lib/python2.7/site-packages/nordicsemi/dfu/dfu.py", line 90, in _dfu_send_image
   self.dfu_transport.open()
   File "/home/akeshava/.local/lib/python2.7/site-packages/nordicsemi/dfu/dfu_transport_serial.py", line 206, in open
   if self.__ping() == True:
   File "/home/akeshava/.local/lib/python2.7/site-packages/nordicsemi/dfu/dfu_transport_serial.py", line 321, in __ping
   resp = self.dfu_adapter.get_message() # Receive raw reponse to check return code
   File "/home/akeshava/.local/lib/python2.7/site-packages/nordicsemi/dfu/dfu_transport_serial.py", line 133, in get_message
   byte = self.serial_port.read(1)
   File "/home/akeshava/.local/lib/python2.7/site-packages/serial/serialposix.py", line 501, in read
   'device reports readiness to read but returned no data '
   serial.serialutil.SerialException: device reports readiness to read but returned no data (device disconnected or multiple access on port?)

   Does this mean that we can't use DFU over serial at 1M baud rate?

[Susheel Nuguru]

Did it work for lower baudrates? I am assuming that you are using hardware flow control in UART. If not, then there is a high possibility of buffer overflows at this high data rate.