Virtual machines with the environment to compile firmware for the latest sources have been made available at:
All you need to do, is to enter the ESP8266-Firmware file located on the screen and start the BUILD. Then with the ./build.sh you can compile selected firmware.
./build.sh – to see the list of available firmware
./build.sh nazwa – to compile the firmware
To update the sources, you have to start the terminal and complete the task: