: Unplug power, press and hold the Reset button, plug power while holding for ~10 seconds. The power LED blinks rapidly. Then use 192.168.1.1 with TFTP to flash original firmware.
Occasionally, firmware updates enable better support for newer encryption standards (like WPA2) or improve VoIP performance. pirelli adb prg a4201g firmware link
Connect your computer to the router using a physical . : Unplug power, press and hold the Reset