To T.DL. : Ok ! I don(t know about the authenticity of the STLINK/V2 I have, but it 'looks' ok (for what it's worth); once both devices connected, I'll have a look at the voltages present @ JTAG pins 1,2 & 19 on the target board side, as they are acc...

To P.B. : Yes, this board is custom (from China), and comes w/ an LCD 320x240 screen ILI9341 driven; when USB-plugged alone on a Win7 PC, it turns on, does some self tests, and then tries to communicate w/ his host (PC). Having no driver of any kind ...