CHIP_EN MUST be driven high by your board. If it's not high, you must figure that out first. Normally, that's a pretty simple circuit (a pull-up resistor, and probably a reset switch). If that pin is not at 3.3V, nothing is going to work.

Ah, well, turned out to be an issue between the ESP32 and our secondary MCU, fundamentally caused by pre-emption of my task causing an unexpected timeout on the secondary side. Thanks for looking, but there's no problem here.

Not that I know of.
I know your pain, and have thought that this would be an excellent addition to 'C', especially in the embedded world, but sadly that's unlikely to happen.

If I can't figure out a workaround, I'll do that. Trying to avoid it because it's probably a days worth of work, but I understand that sometimes that's the only way. I was hoping that someone could say "Oh, yeah, we see that all the time and the workaround is....". But I was hoping that my lottery t...

Sorry if this has been asked before, but searching the forum fails with a 500 error code, and my normal backup of using Google search of the site didn't find anything. What I have: ESP32-C3, ESP-IDF 5.1, ESP-Matter 1.1 What I'm trying to do: Use the ESP32 UART port to reflash a secondary MCU. What I...