ESPEasy
From Lolly's Wiki
$ sudo apt install --yes esptool
$ wget https://github.com/letscontrolit/ESPEasy/releases/download/mega-20200515/ESPEasy_mega-20200515.zip
$ esptool --port /dev/ttyUSB0 --baud 9600 write_flash 0 ESP_Easy_mega_20200516_test_beta_ESP8266_4M1M.bin
esptool.py v2.8
Serial port /dev/ttyUSB0
Connecting...
Detecting chip type... ESP8266
Chip is ESP8266EX
Features: WiFi
Crystal is 26MHz
MAC: 3c:71:bf:2a:a6:0b
Enabling default SPI flash mode...
Configuring flash size...
Auto-detected Flash size: 4MB
Erasing flash...
Took 2.33s to erase flash block
Writing at 0x000dbc00... (87 %)