After downloading firmware into STM32 via JTAG, if I put off the JTAG cable, the board doesn't start. And a reset through the NRST pin does not reset ... Then, MCU is freezed. I have to completly turn-off and on the power in order to reset the board, and then the NRST pin can reset the MCU. Why can't we just reset the MCU through NRST pin after programming the target through JTAG ? Thanks for help. Best regards, V.