I didn't even have to replace my daughterboard -- I ordered a used one, but simply "reseating" (removing and attaching it again) the ribbon cable to the daughter board fixed my problem that the WiFi and Bluetooth card was invisible to the OS.
Thanks anyway for these great instructions! Without them I hadn't even thought about that the WiFi functionality was on a daughterboard... I thought other than in most "Windows laptops" that functionality was integrated into the main board.
Definitely NOT true for MY Mac. Both screws are absolutely identical. Still I had this issue. :-(
Turned out that if I screw them in real tight the issue will occur. If I turn back the screws about 180 degrees (i. e. if I loosen them) the problem disappears.
Thanks a lot for this detailed instructions. It took me far more than only 15 mins (as one of the fellow commenters wrote), more like 1.5 hrs, but I was very cautious not to cause any damage, and I sticked all the screws to the printout I made from this page.
Thanks a lot for this great advice. I followed it, and it turned out to be very useful and practical.
Same happened to me. No damage here either. :-)
That was a great hint, thanks!