Can't get RTT working on L15 using J-Link Plus.

[Calvin T]

I can flash the chip. I can run the debugger. I can go to the connected devices, select the device, go to the little "plug" symbol on the RTT, and select it. That brings up a window asking me to select a device. I select the j-tag device, and then select the processor. It appears to work, but then when I try to run the debugger, I get this:

[00:00:00.390,843] <inf> eeprom_drvr: EEPROM initialized
[00:00:00.391,242] <inf> rgb_led_drvr: LED driver initialized
*** Booting nRF Connect SDK v3.0.0-3bfc46578e42 ***
*** Using Zephyr OS v4.0.99-3e0ce7636fa6 ***
[00:00:00.391,493] <inf> sp_log: Initializing Device: smartpac_l15_eval

[00:00:00.393,514] <inf> fs_nvs: 2 Sectors of 4096 bytes
[00:00:00.393,521] <inf> fs_nvs: alloc wra: 0, f10
[00:00:00.393,525] <inf> fs_nvs: data wra: 0, 120
[00:00:00.393,614] <inf> bt_sdc_hci_driver: SoftDevice Controller build revision:
c7 53 7d bc 06 12 f7 c0 b3 3a 3e 28 8e 56 1e d7 |.S}..... .:>(.V..
a0 be 95 b0 |....
[00:00:00.395,368] <inf> bt_hci_core: HW Platform: Nordic Semiconductor (0x0002)
[00:00:00.395,386] <inf> bt_hci_core: HW Variant: nRF54Lx (0x0005)
0m
m

And then nothing else. A colleague has repeated the process, and the RTT works fine on their system. I'm running nrfutil-device 2.11.0. The nRF connect toolchain and SDK are both 3.0.

Any thoughts?

[Simonr]

Hmm, okay that's strange. Can you check out this ticket and try my colleague Amanda's suggestion as there seem to have been some changes to RTT logging on the latest VS Code extension versions.  RTT debugging not working on nrfConnect for vs Code 2025.4.106 

Let me know if that makes a difference for you or not. Sorry about the late reply  by the way, but last week had a bank holiday here in Norway, so we've been a bit short staffed.

Best regards,

Simon 

[Calvin T]

No worries, Simon.

Here's my launch directive:

    "launch": {

        "version": "0.2.0",

        "configurations": [

            {

                "type": "nrf-connect",

                "request": "launch",

                "name": "Launch core",

                "config": "${workspaceFolder}/core/build/core",

                "runToEntryPoint": "main"

            }

        ]

    }

As you can see, there's no serverArgs directive.