Added instructions for flashing firmware using esptool.
## Summary
Instructions for flashing a specific firmware from the terminal using
`esptool.py`.
## Additional Context
Not everyone has Chrome or Chromium installed. An alternative to the
web-based firmware utility shouldn't be hard to find.
---
### AI Usage
Did you use AI tools to help write this code? _**PARTIALLY**_ : `dmesg`
command analog for MacOS
