I have a Discovery board DISC1 version (february 2016 revision).
I had programmed a Discovery board before with no issues. The ones that I more recently bought, the DISC1 version, 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 the LD2 red led turns on, but nothing else happens. The rest of the board is off.
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.
Does anyone have a clue why this is happening?