Added 1220mah battery. Problem is gone.

I've become fairly convinced that power is my problem, and very likely yours. Using a shorter & fatter USB cable seems to have helped a lot, though it surely doesn't work on all my USB ports, but it's been suggested (by someone who seems to know what they're talking about) that this could be due to ...

I've had a very similar experience (from Mac OSX). ESP32 board was working fine for simple stuff. But after I tried SimpleWifiServer the first time, I was no longer able to upload another sketch (got message "could not open port /dev/cu.SLAB_USBtoUART"). But if I then move to another USB port, or an...