CPU load during HTTP response can get sockets stuck

any idea why I'm getting FIFO full immediately after starting an AP as per my post:

I noticed that too just now - I think it's the big splurge of data the ESP8266 sends out right after it's reset. Most likely it's because of the way data is stored in the UART buffer. UART data is normally packed densely, but if there's a framing/parity error it is also stored in the FIFO, but it takes the space of 4 (sometimes 8) characters - so it doesn't take much of the ESP8266's 76800 baud boot transmission to fill the FIFO up :(

There should now be a WiFi build in http://www.espruino.com/binaries/travis/­5fd503c0b6ae7a24f044e23fa3f7a8690ce7fed7­

If you then try that and then this slight modification of your code (note I'm not using an AP in my case):

function onInit() {
  wifi.connect(WIFI_NAME, { password : WIFI_KEY }, function(err) {
    if (err) {
      console.log("Connection error: "+err);
      return;
    }
    console.log("Connected!");

    wifi.at.cmd('AT+UART_CUR=115200,8,1,0,2\­r\n', 10000, function (data) {
      console.log(data);
      if (data === 'OK') {
        Serial2.setup(115200, { rx: A3, tx : A2, cts: A15 });

        wifi.getIP(function(err,ip) {
          console.log("IP address is http://"+ip.ip);
          createServer();
        });
      }
    });
  });
}

It'll enable proper hardware flow control for the Espruino WiFi and it should start working. It now reliably loads all pages for me even with your indexVERYBAD.