I can no longer upload a program to my STM32F746G-DISCO [SOLVED]

Mbed Studio
1

Hello,
After a long period without using MBED and after updating Mbed Studio (1.5.0), on 8 November 2025 I was able to upload one of my programs to my STM32F746G-DISCO. The next day, this card was no longer automatically recognised by Mbed Studio, so I configured it manually to be recognised. Then all upload attempts ended with this error message: pyocd.core.exceptions.DebugError: No cores were discovered! And of course, the upload did not work.
Mbed is installed on KUBUNTU 24.04. I also tested it on Windows 11, where the board was recognised, but the upload still produced the same error message.
I don’t know if this is a problem with Mbed Studio or if there is a problem with my board.
I will be able to test a second board of the same model tomorrow. In the meantime, if you have any ideas that could solve this problem, I would be interested to hear them.

Marc.

2

I just tried again (on KUBUNTU):
First, I got the same error, then I mounted the STM32F746G-DISCO on my file system (this is suggested when connecting the board, but is not done automatically by UBUNTU). Then the upload worked!
What’s strange is that each time you upload, the card disconnects from the file system, so you have to reconnect it before uploading again.

Until now, I had never had to do this to upload a programme.
Marc.

3

You could try updating the firmware on the STlink built into the board

4

Thank you for your reply. I had already updated the STM32F746G-DISCO firmware.

Marc.