Typically, most IP cameras have a reset pushbutton. Push and hold the button while connecting power, hold for 30 to 60 seconds, and it's reflashed to factory standards. The button may be hidden behind the plastic cover. Check for pinholes in the plastic cover, possibly with RESET or RST embossed/imprinted near them. Otherwise, unscrew/remove the bottom cover, and look for either a pushbutton or pair of contact points on the printed circuit board.