ESP8266 Community Forum

Does anyone know if ESP8266 GPIO holds the last state. I am using one of the GPIO ( GPIO5 of esp-12) as an input from the switch. When switch is closed it sends 5 volt signal to GPIO which change the state to High. But when switch is open, it still keep the state high. I am using LUA firmware. Do I need to use pullup/down resistor to change the state?

Did you feed 5V to the ESP8266 without level shifting? You might have fried (a part of) your module. The inputs are not 5V tolerant, and operating them with 5V input signals will cause most likely damage to the chip.