Router Login Page Hack

Hi,

I am trying to get access to a router login page without user name and password, I know the method of bruteforcing by Hydra but it is too time taking. So, I goggled and found to hack it by deleting a certain HTML part, but I am confused. I don't know which part of HTML I have to remove as I don't have enough command. So can you help me. I will be grateful.

Below is the HTML.

If you have any other ways then please tell me (except brute forcing).