For Windows you can use the official Firmware Download Tool by Espressif!

Settings:

• Baud rate 115200
• Flash size 4MB (megabyte) or 32mbit (megabit) (depending on your module)
• Flash Mode DIO (or QIO, depending on your module)
• 0x0000 rboot.bin
• 0x1000 blank_config.bin
• 0x2000 eve_weather_xxx.bin
• 40MHz

For MacOS you can use this flasher tool!

Settings:

• Erase flash - yes
• Baud rate 115200
• Flash size 4MB (megabyte) or 32mbit (megabit) (depending on your module)
• Flash Mode DIO (or QIO, depending on your module)
• File: eve_weather_xxx.bin
• 40MHz

We have to install esptool.py on our Mac in order to be able to flash our ESP module. To work with esptool.py, you’ll need either Python 2.7, Python 3.4 or a newer Python installation on your system. We recommend using the latest Python version, so go to Python’s website and install it in your computer.

With Python installed, open a Terminal window and install the latest stable esptool.py release with pip:

pip install esptool

Note: with some Python installations that command may not work and you’ll receive an error. If that’s the case, try to install esptool.py with:

pip3 install esptool
python -m pip install esptool
pip2 install esptool

After installing, you will have esptool.py installed into the default Python executables directory and you should be able to run it with the command esptool.py. In your Terminal window, run the following command:

esptool.py

With esptool.py installed on your computer, you can easily flash your ESP8266 board with the firmware.

At first you need to download three bin files: rboot.bin and blank_config.bin. and the latest release. The rboot.bin contains the bootloader for the ESP8266 and the blank_config.bin in just a blank config file and ledstrip.bin contains the firmware. Now connect your device to your FTDI adapter in flash-mode.

rboot.bin
blank_config.bin
main_firmware.bin

To enable ESP8266 firmware flashing GPIO0 pin must be pulled low while powering the device. Conversely, for a normal boot, GPIO0 must be pulled high or floating. Start in FLASH MODE

Go to the directory you made where you put the previously downloaded rboot.bin blank_config.bin files (e.g Downloads)

Open the Terminal app. Click the Finder icon in your dock. Click Go. Click Utilities. Double-click Terminal. Change to the downloads directory.

You'll need an USB TTL adapter for connecting to the ESP8266. If You using a Wemos D1 Mini only needed is a microUSB cable, the Wemos has TTL adapter built-in.

cd downloads

Note: If You using an another library for storing the three .bin files, navigate into that library using cd command :

Use esptool.py to flash your device. First we need to erase the flash:

esptool.py -p /dev/<your_ESPPort> erase_flash

Normally, your ESPPort will be something like /dev/cu.usbserial-xxxxxx. Then, set your device in flash-mode again, and flash the new firmware:

esptool.py -p /dev/cu.wchusbserial1420 --baud 115200 write_flash -fs 32m -fm dio -ff 40m 0x0 rboot.bin 0x1000 blank_config.bin 0x2000 eve_weather_xxx.bin

Updating the firmware is the same as first time flashing, except you DO NOT erase the flash before flashing the new one.