2.4 release
esptool v0.4.12 - (c) 2014 Ch. Klippel ck@atelier-klippel.de
setting board to {upload.resetmethod}
error: unknown board: {upload.resetmethod}
known boards are: none ck wifio nodemcu

And the CPU frequency should not be selected in menu. The 'arduino' boards have 80 MHz esp8266.