ESP32-CAM on ESP32-CAM-MB programmer

Previously, I had been using the ESP32-CAM-MB to program an ESP32-CAM, then take it out and put it in the circuit and it was fine. I've just realised it cannot run code when connected to the ESP32-CAM-MB. I'm programming from a raspberry pi 4, the code uploads but the serial monitor causes the ESP32-CAM light to come on and garbage is printed. The second time I connect, there is a message about reset. Pressing the reset button on the ESP32-CAM causes the light to flash. Is it the case the ESP32-CAM-MB is just a programmer and it can't be used to run code?

This link seems to suggest it's just a programmer.

It can run just fine with or without the MB sub-boad. It sounds like you have a mismatch between your sketch baud and the IDE baud.

I use arduino-cli to compile/upload and minicom for serial with the correct baud. Code runs fine off the MB.

Sorry, I only know the standard setup, and I can't help you.

Maybe try to load a blink sketch with some serial output in it using the standard Arduino IDE.