Hi guys! I found solution for controlling 4 steppers - I needed 8 digital outputs to do that.... I found out that if I use GPIO15, esp12 would not restart (pressing on reset button), I left GPIO15, and move it to GPIO5 instead - and now it is working. I have 10k resistor on GPIO15 to GND. If anybody knows way to overcome this issue and still be able to use GPIO15 it would be nice to know what is real cause of this.