hello KasDing,
I know from experience that such problems have a different origin than you think. But first, a few questions:
are you sure it worked before wifi replacement? have you used an ultrasonic cleaner for this motherboard? is there any damage to the radio part of the motherboard (bottom cover next to the battery port)? When the phone is on - does it respond to the rotation of the screen? does/how does the compass work? does/how does a spirit level work? As you can see, there are many questions, because the gps loop is connected with most of the functionalities, from the camera to the baseband and ending. One more question remains: are you sure you soldered the new wifi chip correctly? I have a lot of work with motherboards on which basic mistakes were made by inexperienced technicians or people simply too fast for microelectronics.
hint: wifi to orientate in three-dimensional space, ic chip needs confirmation with "oscar_context_A" and "oscar_context_B" on fields 32 and 33 of the wifi chip. Are you sure you have this connection after replacement?
* regards,
* PS. additionally: check if you didn't throw off the AKG compass when soldering :-) - it also happens :-)