Problem:
When running esptool erase_flash, you an error message like:
esptool.py v2.8 Found 1 serial ports Serial port /dev/ttyUSB0 Connecting.... Detecting chip type... ESP32 Chip is ESP32D0WDQ6 (revision 1) Features: WiFi, BT, Dual Core, 240MHz, VRef calibration in efuse, Coding Scheme None WARNING: Detected crystal freq 41.01MHz is quite different to normalized freq 40MHz. Unsupported crystal in use? Crystal is 40MHz MAC: 7c:9e:bd:f4:60:e0 Enabling default SPI flash mode... Erasing flash (this may take a while)... A fatal error occurred: ESP32 ROM does not support function erase_flash.
Solution:
You are likely using an outdated version of esptool. Use the esptool from GitHub:
git clone https://github.com/espressif/esptool.git
then run it using
cd esptool python3 esptool.py erase_flash