From https://forum.aircrack-ng.org/index.php/topic,1705.0.html
This was tested and works on an XPS 15 9560 with a Killer Wireless 1535 QCA6174
STEPS: 1- Download https://github.com/kvalo/ath10k-firmware/blob/master/QCA6174/hw3.0/4.4.1.c3/firmware-6.bin_WLAN.RM.4.4.1.c3-00059
2- Make a copy of /lib/firmware/ath10k/QCA6174/hw3.0/firmware-6.bin
3- Change downloaded file name, permissions(chmod), owner(chown) and group(chgrp) to match the original firmware-6.bin
4- Run this (replace wlp4s0 with your interface name):
sudo airmon-ng stop wlp4s0 && sudo airmon-ng check kill && sudo modprobe -r ath10k_pci && sudo modprobe -r ath10k_core
5- Replace /lib/firmware/ath10k/QCA6174/hw3.0/firmware-6.bin with the downloaded file
6- Restart PC
7- Unblock rfkill
sudo rfkill list
sudo rfkill unblock wifi; sudo rfkill unblock all
8- Run the following to enable/disable monitoring (replace wlp2s0 with your interface name):
ENABLE:
sudo modprobe -r ath10k_pci
sudo modprobe -r ath10k_core
sudo modprobe ath10k_core rawmode=1 cryptmode=1
sudo modprobe ath10k_pci
sudo airmon-ng check kill
sudo airmon-ng start wlp4s0
DISABLE:
sudo modprobe -r ath10k_pci
sudo modprobe -r ath10k_core
sudo modprobe ath10k_core rawmode=0 cryptmode=0
sudo modprobe ath10k_pci
sudo airmon-ng stop wlp4s0
sudo service network-manager start
9- Proceed
sudo airodump-ng wlp4s0