ESP8266 releases. With XWiFi and without.
The 1M and 2M firmware need xeu.4096.spiffs.bin
4M firmware need xeu.8196.spiffs.bin
xeu.esp01.1M.bin has a different SMBus/I2C pins configured(SDA GPIO2, SCL GPIO0). This is for the ESP-01 modules, because of the limited pinout.
XWiFi Pinout:
GPIO0(D3) - Power Button (Look up XERC2 installation guide)
GPIO2(D4) - Eject Button (Look up XERC2 installation guide)
GPIO14(D5) - LED Red (Look up XERC2 installation guide)
GPIO12(D6) - LED Green (Look up XERC2 installation guide)
GPIO13(D7) - IsPowerOn(connect to any 3.3V which is not always on e.g. on the LPC Port, NEVER 5V)
GPIO4(D2) - SDA(I2C/SMBus Data Line on LPC Port)
GPIO5(D1) - SCL(I2C/SMBus Clock Line on LPC Port)