A storage circuit includes a first storage region, a second storage region, a third storage region, and a fourth storage region. The first storage region stores first firmware data. The second storage region stores second firmware data. The third storage region stores first state data corresponding to the first firmware data. The fourth storage region stores second state data corresponding to the second firmware data. One of the first firmware data and the second firmware data is executed based on the first state data and the second state data. In a situation that the first firmware data is executed, the second firmware data is updated if a firmware updating event occurs.