First thank  you M.Guru DeLorean, you put me in the right track.As you mentioned, the HSE is generated by the STLINK.My code is dependent of HSE but the STLINK is supplied by E5V through U3, so it is supplied anyway and should generate the clock. For...

I nearly in the same case, but with F439ZI.I have more than 20x  nucleo-F439ZI set with E5V, No JP1 with the same identical program.On an average of 1 board out of 3, I have the behavior explained above. (and not for the others). I first try with dif...