ESP32 Forum

I have a device with a large number of connections, and I'm trying to conserve as many GPIO pins as possible.

Would it be safe to use GPIO0 and GPIO3 with the I2C or I2S peripherals? I know these pins are needed by the serial bootloader, but they aren't needed once application code is running, right?

I've verified this experimentally and it does actually work. I'm able to detect an I2C device and read registers, even while using the serial monitor. I assume that sending bytes via the monitor could cause issues, but I don't plan to be doing that in my use case.