STM32 WB55RG sudden fail

[matteoballotta]

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Board: STM32 WB55RG

OS: Ubuntu 25.10 questing

Kernel: x86_64 Linux 6.17.0-6-generic

STMCubeProgrammer Version: v2.21.0

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I recently noticed that my board was not being flashed with the following error:

No STM32 target found! If your product embeds Debug Authentication, please perform a discovery using Debug Authentication

I tried connecting the board using the STM32CubeProgrammer and while the board is recognized correctly by ST-LINK (the serial number shows up) I still cannot connect the board because of the same error.

When the issues started to occur, I was using my board normally with the usual code running when the board suddenly stopped providing power to the pins; I was using the board to power an external device using the 5 V pin, but my meter only measures about 1 V across the 5 V pin and GND and 200 mV across 3.3 V and GND.

Connecting the board still shows bicolor LED blinking and the LED 4 is always on which I was told it indicates over currents somewhere on the board.

The board also has this fail.txt file when connected using USB:

The interface firmware FAILED to reset/halt the target MCU

I believe the board might be unrecoverable, but I would like to know if anyone has ever had similar issues, if it's common or what might be the causes.

Thanks in advance.

[Andrew Neil]

Welcome to the forum.

You need to give some more details - please see How to write your question to maximize your chances to find a solution.

In particular:

• What board are you using?
• What CubeProgrammer version, and on what OS?

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@matteoballotta wrote:

the board suddenly stopped providing power to the pins..

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Please clarify what you mean by this?

Does your code put the CPU to sleep and/or disable/reconfigure the debug pins?

See also these Knowledge Base articles:

How to solve connection errors when connecting and programming the STM32 target board.

How to solve debugger connection issues.

[matteoballotta]

Thanks for your reply.

I added some details.

- Does your code put the CPU to sleep and/or disable/reconfigure the debug pins?

The code only reads data from and ADC via SPI and transmitted them via Bluetooth, it was created using Zephyr RTOS.

I'm going to check out the links you kindly provided; in case I figure out the issue I will update the thread.

Thanks.

[Andrew Neil]

It's best not to edit a post after it's had replies - it disrupts the "flow" of the thread.

You still didn't say what board you're using: WB55RG is just the chip;  it doesn't specify a board.

Also, what did you mean by, "the board suddenly stopped providing power to the pins" ?

[Ozone]

I don't know the WB55 MCU in particular, to add this first.

But in most cases like this, the board is "bricked" by a critical bug the developer introduced.
In some cases this is an unhandled exception, leading to a core lock-up.
In others, the startup code fails early while initialiing clocks and memory.

The usual solution is to start into a system mode by pulling boot pin(s) to a certain logic level while turning on power.
This is usually described in the user manual of your (undisclosed) board.

Once the board is started into the ROM-based system bootloader, do a mass erase, usually with the CubeProgrammer.

[Gyessine]

hello @matteoballotta 
can you verify the target voltage detected using cube programmer?

Also did you try to connect to it after putting it in BOOT0 ?

BR
Gyessine