nRF Connect for VS Code extension version 2026.6.2030 error when flashing with J-Link

[Rory]

Yesterday, I upgraded to nRF Connect for VS Code extension version 2026.6.2030 and restarted VS Code, and now no matter what I do, the 'Flash' button in my project just pops up the error message "Cannot read properties of null (reading 'padStart')". I am flashing using a SEGGER J-Link. I've tried completely wiping the workspace by deleting the AppData/Roaming/Code/User/workspaceStorage directory, but the error persists after re-opening the workspace.

If I downgrade the extension to 2026.4.1766 it works fine again like it did before this upgrade, so it looks like something in 2026.6.2030 broke the 'Flash' ability with the J-Link.

[Syed Maysum Abbas Zaidi]

Hi,

Thanks for reporting this issue on the VS Code extension version 2026.6.2030. Can you please tell which device/board are you using and also the serial number?

Best Regards,
Syed Maysum

[Rory]

I'm using a custom board with an nRF9160 on it. The serial number of my J-Link is 609788888, and all the other serial numbers shown in my screenshot are FTDI serial adapter devices connected to my computer. The device with the blank/empty serial number shown is an Otii Arc power measurement device I am using for testing. It has a COM port for some reason, and that is why it is shown in the list.

The null or empty string for the serial number of the Otii Arc is definitely what is causing the problems with the 'Flash' task in 2026.6.2030. This makes sense, since it looks like a feature was added to remember the last selected device to flash. I think this feature needs to guard against the case where a device's serial number is null.

[Syed Maysum Abbas Zaidi]

Hi

Thank you so much for the detailed investigation, this is incredibly helpful. You are correct that this needs to be fixed, we have noted it and our team will work on resolving it.

Best Regards,
Syed Maysum