No Serial Output When Flashing Matter Application to nRF54L15 Internal Flash

[xiongwei.wang]

Hello Nordic Team,

I'm experiencing issues when trying to flash my Matter application to the internal flash of the nRF54L15. I've followed the guidance from this forum post: [NCS2.7.0]nRF54L15PDK Matter Internal flash issue - Nordic Q&A - Nordic DevZone - Nordic DevZone

While compilation is successful, I'm not getting any serial output from the device. I've checked and modified my `prj_release.conf` file to enable various output options:

```
CONFIG_USE_SEGGER_RTT=y
CONFIG_SHELL=y
CONFIG_OPENTHREAD_SHELL=y
CONFIG_CHIP_LIB_SHELL=y
CONFIG_CONSOLE=y
CONFIG_UART_CONSOLE=y
CONFIG_SERIAL=y
CONFIG_LOG=y
CONFIG_LOG_MODE_MINIMAL=y
CONFIG_ASSERT_VERBOSE=y
CONFIG_ASSERT_NO_FILE_INFO=n
CONFIG_PRINTK=y
```

Even after recompiling with these settings, I still don't see any output.

I'm developing a Matter project using NCS v3.0.0-rc1 with the official nRF54L15 development board. I'm trying to verify the internal flash OTA process, but I'm stuck because the application produces no output.

Thank you for your help!

[Maria Gilje]

Hello,

I don't have nRF Connect SDK v3.0.0-rc1 installed, so I investigated on v2.9.1. I'll install v3.0.0 if my below questions are not helpful.

Have you tried both COM ports, or even RTT? On my nRF54L15DK (v0.9.2) I get logging on a COM port (VCOM1 in the nRF Connect for VS Code extension).

Is your Matter project based on one of the nRF Connect SDK samples? I used the Matter: Light bulb sample and added the Kconfig symbols you mentioned to prj.conf and prj_release.conf and I got logging in both cases.

What is the reason for you using prj_release.conf instead of prj.conf when prj.conf for the Matter samples already has logging enabled?

Oh, and a small heads up: here in Norway the next few working days are all public holidays, so I won't be back until Tuesday. Apologies for the inconvenience.

Best regards,

Maria

[xiongwei.wang]

Hello, Maria

I only used a serial terminal to check the messages, as other Matter projects could output logs successfully after being flashed.  

My project is based on the **Matter Template** (saved to internal flash) without modifications. I switched to the template to troubleshoot because my original project wasn’t working.  

Regarding `prj.conf`: The linked post I shared earlier mentioned adding compilation options using `prj_release.conf`, but I forgot to include that configuration in my screenshots—it wasn’t that I didn’t try it. Before posting my question, I had already deleted the `build` folder, so the screenshots in my post only show the compilation options I tested (which produced no output).  

I will try **ncs v2.9.1** tomorrow and share the results with you.  

Lastly,have  a nice holiday!  

[xiongwei.wang]

Hello Maria,
Thank you for your help. I learned about the compilation options from the AI assistant on the forum. It told me to use the command 'west build -p -b nrf54l15dk/nrf54l15/cpuapp -- -DCONFIG_CHIP_DFU_OVER_BT_SMP=y -DFILE_SUFFIX=internal`. I used this command for compilation and checked the output during the process. It indeed utilized as series of internal files for the build. And I was able to observe the serial port output.
I really appreciate your response.
Best regards,,
wang