Flashing board first time always fails, need to flash second time

[WoutWG]

Hi,

I am running into this issue that is not critical but annoying to the point that I would like to understand what is happening and to see if it can be solved, since it shouldn't be this way and it's taking some time.

I am developing a firmware using nRF Connect SDK and Visual Studio Code (including the NCS extension). Currently I am targeting the nRF52840 on a nRF9160/PCA10090 DK v2.0.1, but I have also observed this happening on a nRF52840 DK/PCA10056 v3.0.1 so I don't think this is hardware specific.

Whenever I try to program the board (either by clicking 'Flash' in the NCS extension sidebar, or also by directly invoking nrfjprog from a command line) it fails the first time. The board also disappears for a second from the 'Connected Devices' tab in the NCS extension sidebar and I hear a Windows chime to indicate a USB device has disconnected and reconnected again. I then just need to start the flashing process again and then it works, without any failure. It's not clear to me why it fails the first time. 

I did the process once with --log parameters passed to nrfjprog to get the log file, see attached. The first sequence (10:32:51 timestamp) is the failing one, the second sequence (10:34:00 timestamp) is the successful one.

I noticed that both my versions of nrfjprog and JLink DLL were not the latest one, so I updated that since, but I'm still encountering the same issue.0728.log.log

[Amanda Hsieh]

Hi, 

Please update the nRF Command Line Tool to the latest version, and run "nrfjprog --recover" before programming.  

If you still have issues, please provide the log again. Thanks. 

Regards,
Amanda H.

[WoutWG]

Hi Amanda,

Thank you for getting back to me. I haven't had the issue anymore the last couple of days, so it seems that the update indeed helped. It's strange that I did already try to update while posting the question and then it still failed, but it may be that a restart of my PC was required for it to take effect. I'll assume this is solved for now, but I'll let you know if I do encounter the issue again.