So today I went to exchange my WiFi module, old one with newer with holes but not new. Removed old one, connected all cables, started, it works ok. Screw those shell screws lets try to start it, POOF NOTHING ! So battery goes all 4 LEDs and then I hear silent click and that is it. My legs were dead, I thought mainboard is burned so I am throwing this POS which drinks my blood for like 2 months. Unscrew the shell, unscrew that small screw ( coz I knew that I did not touch anything else ), put battery in, and starts ! Then I remove WiFi to see if I got the holes for plastic ok, put it back, screw that small screw whole way down, NOT STARTING ! Unscrew it by half, IT STARTS ! So basicaly Phantom is completely dead when I tighten this screw. I remove WiFi and see that the only pount where the WIFI housing can make contact is on those **** 2 wires for ESC, they are right below the WiFi. I put small electrical fabric tape on those poles, put small patch on the wifi, put 5-6 layers of doublesided tape under WiFi so it goes up for like 1mm and tighten that small screw to little over a half, that tape is holding it ok. So, my conclusion for all those "full battery and sudden drop from the sky" is that because of the vibrations it connects WiFi housing on one of those 2 wires from ESC and it immediately goes dead, completely dead. Does this make sense to you ? I am 90% sure that I could not start it when that small screw was fastened and on that side it can make contact.