Configure network and default password

I tried to configure the preinit ip address in menuconfig but this address is not reachable. Only is and ssh is opened without a password. Is there any way to change this address and set the default ssh password?

Did you change default ip in here?

I have changed it too and compiled firmware but i did not flash yet. So it will not work right?

I am also interested to make my own configuration to the firmware and compile it. So that when i install it will be configured already.