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Associate
March 5, 2026
Solved

DEV_USB_COMM_ERR for REAL St-link V2

  • March 5, 2026
  • 4 replies
  • 321 views

I bought an ST-link V2 from amazon, this error occured, fearing it may be counterfeit, I then bought another St-link v2 from STM website itself so there is no way it is fake, but the same error still occured. I am on Mac M3 using Cubeprogrammer. There is utterly no documentation on this error. What do i do.

Best answer by TDK

Until it says the board has power, it's not going to work. Recheck your power distribution. You haven't shown any of that information here.

Is this a custom board? Is it designed properly? Oriented correctly? VCAP voltage there?

Take a multimeter and measure that voltage is getting to the chip. If it's not, track down where it's lost.

4 replies

Amine_Jridi
Technical Moderator
March 5, 2026

Hello @OWENL,

Could you give more context? As shown in the logs, there is no voltage in the ST-LINK, you can try the following:

- Check your hardware setup.

- Update the ST-LINK firmware and use the latest CubeProgrammer version.

 

If the issue still persists, please provide more information (OS arch, STLINK Led state ....).

 

Thanks,

Amine.

 

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OWENLAuthor
Associate
March 5, 2026

Thanks for your reply. 
1. When i click on firmware update -> open in update mode, i get "error connecting to ST-link, check usb connection and refresh device list"

2. my hardware set up : Since im on a mac, i have the Gray cord's usb end connecting to a usb to usb -c  adaptor, which is conneected to my mac. 

3. THe St-link's LED is red, so there is power, but idk why it still says 0.0V

I think the issue is to do with my USB to USB-c adaptor causing connectivity issues. Ill try to switch to a windows PC and see it it works

TDK
Super User
March 5, 2026

0.0 V is the board power, not the power on the ST-Link.

You will need to power the board and connect power from the board to pin 1 on the st link.

 

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TDK
Super User
March 5, 2026

Screenshot 2026-03-05 083108.png

If the voltage is 0.00 V, it's not going to run. You need to power the board before connecting to it. The programmer does not typically provide power.

"If you feel a post has answered your question, please click ""Accept as Solution""."
OWENLAuthor
Associate
March 6, 2026

Also, what does it mean by debug authentication?

TDK
TDKBest answer
Super User
March 6, 2026

Until it says the board has power, it's not going to work. Recheck your power distribution. You haven't shown any of that information here.

Is this a custom board? Is it designed properly? Oriented correctly? VCAP voltage there?

Take a multimeter and measure that voltage is getting to the chip. If it's not, track down where it's lost.

"If you feel a post has answered your question, please click ""Accept as Solution""."