Nucleo U545RE-Q FAILED to reset/halt the target MCU

[senthilk]

Hi 

I am having trouble to fixe Nucleo U545RE-Q connection error, can someone give detailed instructions to fix the issue

FAIL.TXT

The interface firmware FAILED to reset/halt the target MCU

DETAILS

Version: V3J17M10
Build: Oct 17 2025 15:12:06

Cube Programmer Log

[Mike_ST]

Hello,

It seems like the MCU is not powered. You might have some jumper missing.

Please check the user manual, I believe there is some info about the jumpers:

MB1841 Documentation 

[senthilk]

Hi Mike
Thanks for the info, I have JP4, JP5 JP3 on STLK and CN11 and CN12 jumpers on
Thanks
senthil

[Andrew Neil]

As @Mike_ST said, your Target has no power:

[senthilk]

Hi Andrew
thanks for the post, is that my board can't be booted?

my LD3 flashes twices and then goes solid green

thanks

[Andrew Neil]

Of course - with no power, it cannot do anything !

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@senthilk wrote:

my LD3 flashes twices and then goes solid green

---

LD3 shows that 5V power is reaching the ST-Link, via the CN1 USB connection:

But power is not reaching the target MCU - so, as @Mike_ST said, you need to check the board configuration.

Perhaps post some good, clear, close-up photos of your board ...