trying to write/read a string (variable length) to persistent storage on Nano 33 IOT about flashstorage HOT 3 CLOSED

char xx[]="some string of dummy data";
if(EEPROM.isValid()){
    Serial.println("config present");
    Serial.println("using stored data");
    //  create a buffer
    char x[sizeof(xx)+10];
    // clear it, expect we will read less data than buffer size, most of the time.
    memset(x,0,sizeof(x));
    // loop thru the eeprom (whatever it is) 
    for (int i=0; i<sizeof(xx)+10; i++) {
        Serial.print(" ");
        // get a character
        unsigned char y = EEPROM.read(i);
        // if its not a null terminator (c stringish)
        if( y != 0){
          // save it in the buffer  
          x[i]=y;
        }
        // done with the read loop
        else
          break;
    }
}