Suddenly I was unable to reflash a pair of ESP8266 boards (one nodeMCU, and one Wemos D1).
I had been using those for testing/developing a remote temperature and humidity sensor station with Arduino (C++) and MicroPython for over a year, but yesterday they didn’t work any more. The error was
gabriel@gear:~/.local/bin$ ./esptool.py --port /dev/ttyUSB0 --baud 115200 erase_flash
esptool.py v3.3
Serial port /dev/ttyUSB0
Connecting......................................
A fatal error occurred: Failed to connect to Espressif device: No serial data received.
For troubleshooting steps visit: https://docs.espressif.com/projects/esptool/en/latest/troubleshooting.html
I tried every trick and hack found on the Internet, to no avail (I tried esptool.py from 1.0 through 3.3, grounded I/O pin GPIO0, etc.)
Did I brick my boards forever?