After unplugging ST-Link and reconnecting it I get: Error in initializing ST-LINK device. Reason: (4) No device found on target.

[HSamm.1]

I'm using the STM32H735G DK eval board. Was able to load my code and use the FDCAN ok, when I went on to get the SD-Card going, I found that when reading a block the first 12 bytes would not be transferred. Since I have two boards and so tried the second one, and the result was the same. But switching back to the first one could not get ST-Link connect to the target.

Message: Error in initializing ST-LINK device. Reason: (4) No device found on target.

Going back to the other board the situation is now the same. There were no changes to the hardware or any jumper settings. The boards are powered via ST-Link. Both boards where disconnected with the MCU stopped at a breakpoint and after that didn't work any more.

Any ideas?

[Imen.D]

Hello @HSamm.1​ ,

Do you have still this problem to solve?

Try to connect and program through STM32CubeProgrammer, then please keep me informed about your update.

If you still need help, feel free to ask your question in detail.

Imen

[Tesla DeLorean · Accepted solution]

Spoiler Alert, STM32 Cube Programmer worked.

https://community.st.com/s/question/0D53W00000bg5WpSAI/stm32h735-error-in-initializing-stlink-devicereason-4-no-device-found-on-target