Fortunately, my Fujitsu F-02e was really easy to crack open and i reached the wifi module right after removing the lid. The first thing i noticed by opening the phone was all the dust it had inside even if my phone was Dustproof/waterproof. So i first blowed out all the dust and then rubbed the module a little, trying to find a way to repair my phone. Finally i resigned and put it all back up and then after reboot the wifi worked again!
This is to use only as a reference, to help all of you and people on warranty should NEVER open their phones. I am not responsible for whatever happens if you open your phone and don't guarantee this will solve your problem. Maybe i was just really lucky.
Finally, i'll share you my idea on how this happened. First, my phone is real easy to get hot when on wifi and on gps. And last week, i turned on the dev option keep lit when charging in android dev options so i keep my wifi on and share stuff easily. Then i kept my phone on it's charging station all the day long which might have overheated the device. From now on, i won't ever turn this thing on.
Good luck to all of you having the same issue i'm aware this is a real pain in the ass.
Edit: Also forgot to tell that anybody without experience with phone repairs/disassembly should never attempt opening their own and maybe ask a friend with knowledge instead.
Also i'm ready to help people out opening their F-02e but it isn't hard at all... There is no hidden screws in the phone and i removed 7 including the antenna screw.