How to access my Zyxel N4100 after firmware upgrade only Power LED is on?

Hello:

I need assistance with my Zyxel N4100, after performing a firmware upgrade it is now somehow bricked, cannot access it even when using the reset button. Whey trying the reset button nothing happens, not blinking lights only a steady power light while SYS and WLAN are off.

Please let me know if there another way to reset my device to be able to access it once again.

Thanks in advance

#Biz_WLAN_June