MCX MicrocontrollersのトピックRe: JLink Debug Authentication

JLink Debug Authentication

raimbowgeddon — Mon, 29 Jun 2026 17:29:39 GMT

Hello all,

Im following a project based on the MCXN947 (frdm_mcxn947 board) and we need to setup the debug authentication and signed firmware validation before sending it to the client for testing, but im very unsure about two things.

Is the debug authentication restricted to the "in-field" case? where the MCU is permanently locked with keys and security configuration burned in OTP? I dont want to risk permanently breaking the only board i have
If i set up the debug authentication feature, then is it still possible to connect and debug code with the on board debugger? Im debugging with VSCode with a Jlink debug .launch config, how do i add the security artefacts for enabling the debug authentication?

It would be great if someone that has already tackled the thing can shed some light on how to proceed, because i only see the AN14162 being referred to and not much else in terms of documentation

Re: JLink Debug Authentication

Alice_Yang — Tue, 30 Jun 2026 06:53:14 GMT

Hello @raimbowgeddon

1. Is the debug authentication restricted to the "in-field" case? where the MCU is permanently locked with keys and security configuration burned in OTP? I dont want to risk permanently breaking the only board i have

->>No, the debug authentication is not only for "in-fileld" casse. It can be tested during development. Config it on CMPA part, not in OTP.

2. If i set up the debug authentication feature, then is it still possible to connect and debug code with the on board debugger? Im debugging with VSCode with a Jlink debug .launch config, how do i add the security artefacts for enabling the debug authentication?

->>Yes. After debug authentication is enabled, you normally cannot just start a normal J-Link session as before. You must first run the debug authentication challenge-response flow, then connect your debugger.

There is a video that shows the steps for configuring and using Debug Authentication on the MCXN947. I'm not sure whether you can access it:

https://www.bilibili.com/video/BV13EhAzdEzV/?spm_id_from=333.1387.homepage.video_card.click

Thank you.

Alice

Re: JLink Debug Authentication

raimbowgeddon — Sun, 12 Jul 2026 16:13:29 GMT

Hello @Alice_Yang,
Sorry for the delayed response, i've been caught up with some other urgent work. I just followed the directions given by the video you linked, and it seems to be working! I was missing the piece about unlocking the device from the tool and then simply attaching with the debugger. I also tried to overwrite the image with another one and it works, besides a warning about CFPA region not being written, but i cannot seem to be able to do a flash erase, even if debug authentication step was done, is this expected? Does it mean that now the board will permanently be secured? Is there no way to make the board return to the factory settings now?
Thank you so much for the help
FS