just for completeness ... I've now got the second supermini and it's even worse. After any upload, even blink without Serial.begin(), it refuses further ones until put into upload mode. I'm now using a Raspberry Pi Zero which is much less hassle.

Thanks for the suggestions. I don't have a second board to try, but I've got one on order (which I'm kind-of regretting). The Arduino IDE board manager shows the following installed Arduino ESP32 Boards by Arduino 2.0.13 installed esp32 by Expressif Systems 2.0.15 installed there are no later versio...

I'm an amateur Arduino user who wants to upgrade to something with more RAM. The ESP32-C3 supermini looked good because its small size fits on a breadboard. However, like many people, I have found it very tricky to use. I now have a puzzling situation with a very simple sketch - the basic blink in f...