I have a Discovery board STM32F407G DISC1.
I had programmed a Discovery board before with no issues. The ones that I more recently bought, have a strange issue: after I flash the program, if I connect them to the PC via USB (CN1), everything works fine, but if I power it up with external +5V or with the CN1 (but not from an USB port), the LD1 led start blinking, the LD2 red led turns on, but nothing else happens. The rest of the board is off. The program does not seem to run.
I stress that this never happened with the previous revision of the same board, i always powered it up via external +5V and it always worked correctly.
I also installed the latest ST-LINK firmware using STLinkUpgrade 3.2.2.
The same appears on a STM32F411-DISC0.
Does anyone have a clue why this is happening?