Hold the (boot keys) simultaneously. Connect the device to your PC via a USB cable.
Download the authentic Kechaoda A26 Flash File (Stock ROM) from reputable mobile repair forums or the manufacturer's resource page. Step-by-Step Flashing Guide kechaoda a26 flash file link
Some versions of the A26 may use the "OK" center button or the "Call" button as the boot key instead of navigation keys. Hold the (boot keys) simultaneously