ESP8266 BOOTLOADER

[WantDoIt]

hi~
I want to download WiFi binary file to ERP8266 chip. I have WiFi binary file。I successed by PC tool
to download WiFi binary file to ERP8266 chip. Now,I want to download file by my the C language program code instead of PC tool. I have set ESP8266 chip into boot mode by GPIO。However, I don't know how to communicate with ESP8266 chip boot without ESP8266 Chip Protocol documents.
Can you give me some advice or documents？
Thank you

[nqd]

if you want to look into esp bootloader, here is good reference https://github.com/raburton/rboot since espressif do not document openly.