Yeah... I'm in the same boat. A couple months ago the wifi all of a sudden cut out and it never came back. Camera is fine when using a wired connection to the router, and the wireless site survey works so the wifi isn't fully dead, but it's unable to connect to my wireless. I've tried all the suggestions having the camera right next to the router antenna: changing the channel and channel width, mixed and G-mode only, trying with and without security, different routers, PnP+PnP PF on and off, extender mode always off. It's just not connecting to any wireless networks anymore.
FW: 1.13.05, but I've tried it on 1.12, 1.10, and 1.04. Region: NA/Canada
It's weird because it happened all of a sudden, it didn't happen after upgrading firmware at least not right after. I may have updated the firmware a couple weeks prior.