Hi all, I was struggling with this for some time now and wanted to share what I learnt. Problem: I have MBP late 2013 model 13 inch with 802.11ac wifi card installed. I know it is old but with all the ports (HDMI, SD card, audio jack) and older keyboard version Apple has gone back to in 2021/22. Bluetooth was working fine but not wifi. Wifi connected and dropped randomly. Sometimes would stay connected. Clicking on Apple logo> about this Mac > System Report > Wi-Fi, everything from 'interfaces:' would not be visible, meaning there is issue with AirportBrcmNIC kext (Apple logo> about this Mac > System Report > Extensions > AirportBrmcNIC) showing loaded: No; loadable: Yes. DO NOT WASTE TIME ON THIS... Do not try wasting your time using SMC and PRAM reset as this does not solve the issue. Going to Apple support: They said, if there is a hardware issue, they will charge 25% laptop cost and replace entire keyboard/modem part of the laptop. They were not ready to even check the software and said they would charge basic fees. This may be specific to a Apple support office, where they did not have experts. My understanding The interface related file gets corrupted and may work on and off. If you can specifically update related files, that should solve the issue. If you are not an expert like me, try this... Solution Just reinstalled the big Sur using Command+R after pressing the power button, and connect using a USB-ethernet adapter and ethernet cable for internet. I reset the network settings and that helped temporarily but wifi would drop and on restart may/may not connect. In the finder window, click on 'Go' then 'Go to folder' and copy this /Library/Preferences/SystemConfiguration Copy all the files in another folder for backup. Be very careful what files you delete here as it can affect your network interface and you may stop seeing the Wi-Fi card altogether. They are generally loaded on the laptop everytime you reboot it in the order mentioned You can then delete all the below files and restart. It will ask for your password. If you cannot see the Wi-fi card after restarting, delete the below mentioned files and copy 1 to 4 in the System Configuration folder from your backup folder and restart. Settings.plist com.apple.eapolclient.plist com.apple.network.eapolclient.configuration.plist com.apple.AutoWake.plist com.apple.airport.preferences.plist.backup com.apple.airport.preferences.plist com.apple.smb.server.plist NetworkInterfaces.plist preferences.plist com.apple.wifi.message-tracer.plist com.apple.accounts.exists.plist I repeated the above step along with restarting the router and MBP in safe mode (press and hold Shift key for intel chip Macs). This trick allowed me to have stable enough wi-fi to start reinstalling Mac OS big Sur using Command+R. One last thing, try to have a unique name for your Wi-Fi and use WPA/WPA2 configuration, have only 1 connection saved in Network>Advanced, so your laptop is not trying to connect to multiple saved Wi-Fi connections, this may cause Wi-Fi to drop as well. This may be if you have 'wifiname' and 'wifiname_5GHz' names saved for 2G and 5G internet networks. Other fixes of forgetting the Wi-Fi and reconnecting, adding DNS (8.8.8.8, 4.4.4.4., 8.8.4.4) and other information available online and in this thread are useful and you can try that if your issue is not more upstream. Final thoughts: All in all, I am happy with Apple, almost a decade on and still quite sturdy. May just keep this old one for regular use after buying MBP 2022.