Latest Espruino build for Esp8266

From README_flash.txt:

*** To flash a 4MB esp8266 (e.g. esp-12) using the serial port use:
esptool.py --port [/dev/ttyUSB0|COM1] --baud 115200 write_flash \
  --flash_freq 80m --flash_mode qio --flash_size 32m \
  0x0000 "boot_v1.6.bin" 0x1000 espruino_esp8266_user1.bin \
  0x3FC000 esp_init_data_default.bin 0x37E000 blank.bin

Yours:

esptool.py --port /dev/cu.usbserial --baud 460800 write_flash \
  --flash_freq 80m --flash_mode qio --flash_size 4MB \
  0x0000 boot_v1.6.bin 0x1000 espruino_esp8266_user1.bin \
  0x37C000 esp_init_data_default.bin 0x37E000 blank.bin

I don't have a 12'er, but you use:

0x3FC000 esp_init_data_default.bin

and in the text:

0x37C000 esp_init_data_default.bin

Could it be it?