ESP8266 Community Forum

pzwolinski wrote:I'm having the same problem...

I have an LED connected to between GPIO2 and GND. When my ESP01 is restarted, it will not boot normally, which is a bummer. If I temporarily disconnect the LED circuit, the board will boot normally, and after reconnecting, my program works as desired (able to toggle the LED over wifi).

Is there anything I can do to get this unit booting normally without having to leave GPIO2 floating?

I had the same problem and I fixed with a 2,2k pull up resistor (4,7k or higher was not working).
Doing this GPIO2 will be high by default while it resets (1-2 seconds), but you allways can write to low.

I have the same problem for my project. I am building an electricity meter monitoring device. From time to time the ESP8266/1 will reboot (don't know why...). The sensor is connected to GPIO0, and it is unpredictable when it is HIGH or LOW. So when on LOW the ESP will start up in bootloader mode and just does nothing anymore. Delaying is not an option in my case, so I'm thinking about another sollution. I have only 2 pins (0 and 2) available. GPIO0 as read, and GPIO2 still free. So I will connect an optocoupler to GPIO2, also connected to the senor output.
GPIO0 is pulled up with a 1k resistor, making it HIGH by default. GPIO2 will be programmed to go HIGH when starting "init.lua", activating the sensor with the optocoupler. When rebooting GPIO2 will automatically go on float, disconnectiong the optocoupler and pulling up GPIO1.
I hope this works.

If your module doesn't have GPIO15, it's already connected on the PCB to GND.

I've found that letting GPIO0 float works fine, but if you want to be absolutely sure, pull it up to 3.3V. Same with GPIO2.

I had the same issue while driving the gate of a mosfet using GPIO2. Usually it is recommended to pull-down the gate, so that the mosfet is in a defined state if the uC is reset. With a 10k resistor the ESP-01 wouldn't start up properly. However, using a 100k resistor worked just fine.