You can use the telnet approach as described or have a look at the network menu in the gui. There is an option to set the password there or in some related menu. I don't have access to a box at the moment.How do I find password and root?
I think I used it some 5 or 6 years ago, but have forgotten.

In openwebif, when you type init 4, you stopped enigma2 and also stopped the openwebif you were working in. Not the best of ideas. Would be nice if openwebif could stay alive, but you are very limited with that particular terminal to the point of it being almost useless for most of the tasks that I would do.Other programs like FileZilla, WinSCP.
Most of the values of that file are held in RAM and written on graceful shutdown/restart. So make sure you stop Enigma2 before you start editing. I use Putty. You can use any terminal client, including the one on openwebif. Issue following command to stop e2
init 4
And following to restart
Init 3