Flash a stock rom, make sure you lock the gps onto your location (use gps status/toolbox) and then flash the aosp rom over the stock
Extract the gps.conf from /system/etc of stock and replace your aosp gps.conf.
Try seeing if 'DEVICE ONLY' in location settings allows gps to lock on in aosp, and then switch to 'HIGH ACCURACY' - this worked for me, as high accuracy showed 0/0 sat. found, but device only found 15/21, then my gps worked normally.
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