RAK4631 com19 vanish if access at all by anything. cant get DUF via reset button

Please include the following information, in order for us to help you as effectively as possible.

  • What product do you wish to discuss? RAK4631, RAK3372, RAK11200, RAK11310, RAK11722?
    4631
  • What firmware are you using? (RUI3 or Arduino BSP or other IDE (e.g. STM32CubeIDE)?
    was on 0.4.3 BSP but after the update due to the chip crashing on every flash write. no idea now.
  • What firmware version? Can it be obtained with AT+VER=?
    no option as the com19 vanish from device list if accessed.
  • Computer OS? (MacOS, Linux, Windows)
    windows
  • What Computer OS version?
    11
  • How often does the problem happen?
    everytime
  • How can we replicate the problem?
    just plug in the usb and if i press the rst button within a second I get a green flash from led then a fast blue flash . then nothing and the USB port is gone. if i time everything perfect i can get the wistools to see the port but not fully connect as its gone too fast.
  • Provide source code if custom firmware is used or link to example if RAKwireless example code is used.

There must be a way to get into DFU mode or flash the chip without USB? Please any help is good.
pushing resert twice does nothing but lose the com19
and i tried the CLI way using adafruite-nfrutil too.
this is the output from |CLI
"C:>adafruit-nrfutil.exe --verbose dfu serial --package WisCore_RAK4631_Board_Bootloader.zip --port COM19 -b 115200 --singlebank --touch 1200
Upgrading target on COM19 with DFU package C:\WisCore_RAK4631_Board_Bootloader.zip. Flow control is disabled, Single bank, Touch 1200
Touched serial port COM19

Failed to upgrade target. Error is: Serial port could not be opened on COM19. Reason: could not open port ‘COM19’: FileNotFoundError(2, ‘The system cannot find the file specified.’, None, 2)
Traceback (most recent call last):
File “nordicsemi\dfu\dfu_transport_serial.py”, line 113, in open
File “site-packages\serial\serialwin32.py”, line 31, in init
File “site-packages\serial\serialutil.py”, line 240, in init
File “site-packages\serial\serialwin32.py”, line 62, in open
serial.serialutil.SerialException: could not open port ‘COM19’: FileNotFoundError(2, ‘The system cannot find the file specified.’, None, 2)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File “nordicsemi_main_.py”, line 294, in serial
File “nordicsemi\dfu\dfu.py”, line 226, in dfu_send_images
File “nordicsemi\dfu\dfu.py”, line 157, in _dfu_send_image
File “nordicsemi\dfu\dfu_transport_serial.py”, line 115, in open
nordicsemi.exceptions.NordicSemiException: Serial port could not be opened on COM19. Reason: could not open port ‘COM19’: FileNotFoundError(2, ‘The system cannot find the file specified.’, None, 2)"

Welcome to RAK forum @emumanx ,

When you plug the module, it is detected to be connected to COM19 then it disappears right? No other COM is detected?

I am not sure what upgrade you did on the module but at this point (assuming there is corruption on the uploaded firmware/bootloader), the only option is to use an external tool to clear/erase the memory then upload a new bootloader. It can be jlink, rakdap1, etc.

i have tried to flash the rak4631 module with a RAKDAP1 pyocd and it fails at 17 percents each time
Unexpected ACK value (0) returned by probe
i think the flash memory must be faulty. but trying to get any sense from Wis themselves is crazy.