nRF board not getting detected

[Aadishri GS]

I wanted to try the bootloader related example. I was using the IAR to run peripheral examples.

But for bootloader example, I saw that IAR was not listed. So installed the nrfgo Studio

I understood the softdevice may need to be updated. So used nrfgo. Here, I entered bootloader mode by pressing Reset Button and power-cycling. I selected the softdevice hex s140 from 15.3.0 SDK->Components folder. I was not sure if the Softdevice programming was successfull. But the com-port stopped showing up

Currently,

1. I see no LED glows if I connect the board to the PC

2. If I enable bootload mode using reset button, led 5 glows continuously

3. COM port is not seen anymore

4. Unable to use IAR debugger to download and debug. I get the  option to connect via IP as seen in the attached picture

Can you please let me know what has happened?

[Aadishri GS]

I understood that the J-Link must be the one that I am facing issues with

Answer by @Rajneesh:

1. Press  button-4 + reset while power cycling. As soon as bootloader window pop-up download bin file from below link. Also I attached screenshot for reference.

https://www.nordicsemi.com/Software-and-Tools/Development-Kits/nRF52840-DK/Download#infotabs

2, After download drag and drop bin file in pop-up window and immediately you can see power led start fast blinking. Then start device again by power switch and open nRFGoStudio and now you can see board detected. If it ask to update firmware then click yes and upgrade the firmware.

I recovered my board by following above steps. I am not sure this is right things to recover the board. So, please follow the steps be careful until Nordic can not confirm. I just shared the info to save someone time

[AndreasF]

Hi.

That seems correct in order to recover your board.

I will verify that answer for that question, please create a new ticket if you have any other questions :-)

Best regards,

Andreas

[Aadishri GS]

So basically it was just that the JLink bin was deleted. I am unable to understand where this binary was stored? and why did it get deleted when I probably incorrectly programmed the SD. Is this not a vulnerability?

I am basically worried about making my device unusable just due to the absence of a debug binary

[Aadishri GS]

This can happen if you press the reset button while power-cycling the board. It only affects the interface MCU(jlink lite), not the nRF chip.

[Aadishri GS]

Another useful related link:

https://devzone.nordicsemi.com/f/nordic-q-a/44089/nrf52832-entered-in-bootloader-mode