The ESP32 that I went for is specifically the ESP32-DevKitC, which is easy to find, cheap, and compatible with most things ...

It looks like whatever boot ROM the ESP32 has inside it is testing for a high voltage on GPIO 12. Don’t ask us. Anyway, the short version of the story is: pull GPIO 12 high and hit reset.

BOOT button for the RP2040, to switch between USB-Programming and USB-Host/Device ESP32 reset button and three user LEDs Unpopulated JTAG header for kernel developers EsPiFF features ...