Invalid argument error when running "west rtt" with nRF9151

RE: Invalid argument error when running "west rtt" with nRF9151

Elfving — Fri, 10 Oct 2025 15:29:39 GMT

Sorry about the wait. I am not used to this command, and I am struggeling to find others who are either. Though it seems to me this far that west rtt is automatically using another name for the device than what the RTT Viewer does. If you run west -vvv rtt you get this at the end:

JLinkGDBServer -select usb -port 2331 -if swd -speed 4000 -device nRF9151_xxAA -silent -endian little -singlerun -nogui -rtttelnetport 19021 -nohalt

Although only nRF9151_xxCA is what is listed among the registered target devices in the latest JLink version.

See if it works for you if you change the command to use nRF9151_xxCA.

Regards,

Elfving

RE: Invalid argument error when running "west rtt" with nRF9151

cgnd_chris — Sat, 27 Sep 2025 23:31:08 GMT

Elfving I tried this same process on a nRF54L15-DK board and I'm seeing the same behavior.

Connect USB to nRF54L15-DK
cd /opt/nordic/ncs/v3.1.0/zephyr/samples/subsys/shell/shell_module
west build -p -b nrf54l15dk/nrf54l15/cpuapp/ns --sysbuild -- -DCONF_FILE="prj_minimal_rtt.conf"
west rtt

I get the following error:

❯ west rtt
-- west rtt: rebuilding
[0/5] Performing build step for 'shell_module'
[0/16] Performing build step for 'tfm'
ninja: no work to do.
[2/3] Performing install step for 'tfm'
-- Install configuration: "MinSizeRel"
----- Installing platform NS -----
[3/3] Completed 'tfm'
[4/5] cd /opt/nordic/ncs/v3.1.0/zephyr/samples/subsys/shell/shell_module/build/_sysbuild && /opt/homebrew/bin/cmake -E true
-- west rtt: using runner jlink
-- runners.jlink: reset after flashing requested
-- runners.jlink: JLink version: 8.72a
-- runners.jlink: J-Link GDB server running on port 2331; no thread info available
-- runners.jlink: J-Link RTT server running on port 19021
SEGGER J-Link GDB Server V8.72a Command Line Version

JLinkARM.dll V8.72a (DLL compiled Sep 25 2025 17:23:39)

-----GDB Server start settings-----
GDBInit file:                  none
GDB Server Listening port:     2331
SWO raw output listening port: 2332
Terminal I/O port:             2333
Accept remote connection:      yes
Generate logfile:              off
Verify download:               off
Init regs on start:            off
Silent mode:                   on
Single run mode:               on
Target connection timeout:     0 ms
------J-Link related settings------
J-Link Host interface:         USB
J-Link script:                 none
J-Link settings file:          none
------Target related settings------
Target device:                 nRF54L15_M33
Target device parameters:      none
Target interface:              SWD
Target interface speed:        4000kHz
Target endian:                 little

ERROR: runners.jlink: [Errno 22] Invalid argument

However, if I open the JLinkRTTViewer.app from Segger, the RTT functionality works OK.

RE: Invalid argument error when running "west rtt" with nRF9151

cgnd_chris — Thu, 25 Sep 2025 16:53:44 GMT

I've only tried this on the Thingy:91 X so far. I'll try to test this out on another Nordic dev kit and reply back.

What error are you seeing? I'm on macOS with Apple Silicon, what OS are you using?

RE: Invalid argument error when running "west rtt" with nRF9151

Elfving — Thu, 25 Sep 2025 08:31:33 GMT

Hi again Chris, and sorry about the wait.

I'm also seeing an error doing this, but not exactly what you are seeing. Given that you have more boards on hand, could you see if you're only getting this issue on the Thingy?

Regards,

Elfving

RE: Invalid argument error when running "west rtt" with nRF9151

cgnd_chris — Tue, 16 Sep 2025 21:50:33 GMT

Elfving I saw this on a custom app I'm working on using NCS 3.0.1. I tried reproducing it on the latest 3.1.0 with the sample app to check if it was something specific to my app, but I saw the same behavior.

Are you able to reproduce it on your end using the steps I posted above?

RE: Invalid argument error when running "west rtt" with nRF9151

Elfving — Mon, 15 Sep 2025 10:59:55 GMT

Hi Chris,

Are you seeing this with other samples as well, or just this one for this particular board?

Regards,

Elfving