An arduino program to add MQTT commands to your roomba 500 or 600 series.
https://www.youtube.com/watch?v=t2NgA8qYcFI
To Flash ESP-01: Using breadboard https://ambimod.jimdo.com/2017/01/26/tuto-comment-programmer-un-esp-01-et-l-utiliser-%C3%A0-la-place-d-un-nodemcu/
Dedicated USB adapter
https://www.amazon.fr/gp/product/B07G6ZPY9D/ref=ox_sc_act_title_1?smid=A39E1U5VNJF3OK&psc=1
With Raspberry:
https://blog.3d-logic.com/2017/12/01/using-raspberry-pi-to-flash-esp8266/