No ST-LINK detected on STM32F4-Discovery

AndrewEmbedded · ‎2025-10-06

I'm trying to work with a STM32F4-Discovery board, and previously it connected perfectly okay, but a couple weeks ago something, seemingly out of nowhere, broke and CubeIDE stopped detecting the board and writing programs to it showing this message:

I tried reinstalling the IDE, downgraging the toolchain, upgrading the IDE, creating a fresh project and so on.

I'm running version 1.19.0 CubeIDE, using EndeavourOS (Arch-based).

Here are my udev rules for a relevant device:

# stm32 nucleo boards, with onboard st/linkv2-1
# ie, STM32F0, STM32F4.

SUBSYSTEMS=="usb", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="374b", \
    MODE="660", GROUP="plugdev", TAG+="uaccess", ENV{ID_MM_DEVICE_IGNORE}="1", \
    SYMLINK+="stlinkv2-1_%n"

SUBSYSTEMS=="usb", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="3752", \
    MODE="660", GROUP="plugdev", TAG+="uaccess", ENV{ID_MM_DEVICE_IGNORE}="1", \
    SYMLINK+="stlinkv2-1_%n"

My user is a member of the plugdev group.

But the important detail is that if I run `stm32cubeide_wayland` as root through `sudo` it is able to detect the board. (Still doesn't run the project, but that's because I don't have it setup for root either way.)

Imen.D · ‎2025-10-06

Hello @AndrewEmbedded and welcome to the ST Community,

Check the USB cable or use a different cable (not for charging).

Try physically reset the board by pressing the reset button.

Check also if the debug pins (SWDIO, SWCLK) are free and reserved for debugging.

Please follow the tips provided in this article, this may help you:How to solve connection errors when connecting and programming the STM32 target board

When your question is answered, please close this topic by clicking "Accept as Solution".
Thanks
Imen

Ozone · ‎2025-10-06

I can't see anything wrong with your setup. It used to work for me, although different distros.

Perhaps you could try OpenOCD, and check if it sees your ST-Link.
I suppose lsusb lists it correctly.

mfgkw · ‎2025-10-06

Hello @AndrewEmbedded , maybe (a) the output of dmesg (while connecting the st-link) and (b) long ls output of the devices after connecting could help.

AndrewEmbedded · ‎2025-10-06

Yes, lsusb does detect it, as the system in general, it seems to be some strange permission issue.

AndrewEmbedded · ‎2025-10-06

sudo dmesg -W 
[14788.198887] usb 1-2: new high-speed USB device number 14 using xhci_hcd 
[14788.404324] usb 1-2: New USB device found, idVendor=214b, idProduct=7250, bcdDevice= 1.00 
[14788.404333] usb 1-2: New USB device strings: Mfr=0, Product=1, SerialNumber=0 
[14788.404337] usb 1-2: Product: USB2.0 HUB 
[14788.409492] hub 1-2:1.0: USB hub found 
[14788.412309] hub 1-2:1.0: 4 ports detected 
[14788.724908] usb 1-2.1: new full-speed USB device number 15 using xhci_hcd 
[14789.027405] usb 1-2.1: New USB device found, idVendor=0483, idProduct=374b, bcdDevice= 1.00 
[14789.027413] usb 1-2.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 
[14789.027416] usb 1-2.1: Product: STM32 STLink 
[14789.027419] usb 1-2.1: Manufacturer: STMicroelectronics 
[14789.027422] usb 1-2.1: SerialNumber: 0668FF505356867767124434 
[14789.112448] usb-storage 1-2.1:1.1: USB Mass Storage device detected 
[14789.112700] scsi host9: usb-storage 1-2.1:1.1 
[14789.124519] cdc_acm 1-2.1:1.2: ttyACM0: USB ACM device 
[14790.168895] scsi 9:0:0:0: Direct-Access     MBED     microcontroller  1.0  PQ: 0 ANSI: 2 
[14790.170507] sd 9:0:0:0: [sdc] 6216 512-byte logical blocks: (3.18 MB/3.04 MiB) 
[14790.170692] sd 9:0:0:0: [sdc] Write Protect is off 
[14790.170699] sd 9:0:0:0: [sdc] Mode Sense: 03 00 00 00 
[14790.170921] sd 9:0:0:0: [sdc] No Caching mode page found 
[14790.170928] sd 9:0:0:0: [sdc] Assuming drive cache: write through 
[14790.199522] sd 9:0:0:0: [sdc] Attached SCSI removable disk

I'm attaching it through a hub, as it worked this way before that.

LANG=es_ES /bin/ls -l /dev/ttyACM0 
crw-rw---- 1 root uucp 166, 0 Oct  6 12:29 /dev/ttyACM0

Andrew Neil · ‎2025-10-06

@AndrewEmbedded wrote:
I'm attaching it through a hub, as it worked this way before that.

Have you tried without the hub ?

And on different physical USB ports?

with a different hub ?

https://community.st.com/t5/stm32-mcus/how-to-solve-debugger-connection-issues/ta-p/49693#:~:text=Try%20other%20USB,be%20quite%20fragile.

PS:

@AndrewEmbedded wrote:
previously it connected perfectly okay, but a couple weeks ago something, seemingly out of nowhere, broke and CubeIDE stopped detecting the board

A recent thread found that their ST-Link connection problem was with insufficient power from the host USB port.

Did you change anything to make the board draw more power ?

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

mfgkw · ‎2025-10-06

/dev/ttyACM0 is group uucp. You told your users are in plugdev. I would add them to uucp...

AndrewEmbedded · ‎2025-10-06

Tried without a hub, and with a couple of different ports, but neither helped. And I don't have a different hub, so didn't do that.

AndrewEmbedded · ‎2025-10-06

My user is uucp as well.

id rhinemann -Gn 
rhinemann sys wheel uucp rfkill wireshark plugdev