Solution to this Fault on LG SJ810v
I had the same problem with my 49sj810v (random messages connected- disconnected devices, the wifi could not detect any networks, and the magic mouse could not connect(could not register as the bluetooth had to be initialised)).
SOLUTION: Have replaced the RF Module (EAT63377302 WI FI MODULES & 3D TRANSMITTERS FOR LG GENUINE 49SJ810V).
Now everything is working Fine.
Hope this message will help other LG tv owners that LG will not help.