when soldered to the board I accidentally allied +5v to wrong pin (pd7 probably)
now M1B and M1A stopped working, everything else seems to be ok and I can still flash the micro-controller. I tried motor1 example - only 1 motor runs…
It’s certainly possible to break only part of an electronic system or integrated circuit. From what you’re saying, it could be the AVR or the motor driver that is damaged; you could try probing the leads on the motor driver to see if the signals you expect are coming out of your microcontroller.