I got it! The PC version (not the mobile version) of "iRoot" worked! Coincidentally, the last update is from 15/5/2015, today.
I found some guy that had locked his sim in a forum doing it.
Little did he know, it's probably the first day that worked.
edit: the actual latest version I used is from the non-english site: http://www.mgyun.com/vroot