Tak jedině reset:
Factory Default Reset button
There are two ways to reset the router's factory defaults:
1. Use the Factory Defaults function on System Tools -> Factory Defaults page in the router's Web-based Utility.
2. Use the Factory Default Reset button: First, turn off the router's power. Second, press the default reset button, then turn on the router's power, and hold the reset button until the M1 and M2 LED flash simultaneously (about 3 seconds). At last, release the reset button and wait for the router to reboot.
Note: Ensure the router is powered on before it restarts completely.

viz. http://www.luxus.cz/dokumenty/manual_tl_r402m.pdf