ATTiny85 Serial communication with Bluetooth Module
Hello,

I think you should do this:

char inputChar = '';    //this in global
while (serial.available()) {
    inputChar = serial.read();
    if (inputChar == '2') {    //Char to break
        //Do something and reset i
    } else {
        inputString[i] += inputChar;    //= to +=
    }
    i++;
}