Wifi interface completely gone after catalina update on 2015 MBP

macOS-Catalina-Wifi-Fix.md

Apple Discussion: https://discussions.apple.com/thread/250720965?answerId=251575762022#251575762022 Most Active answer on StackOverflow: https://apple.stackexchange.com/questions/372025/missing-wifi-interface-after-upgrade-to-catalina?newreg=1904677ef3d840f0a87b73a2cd7bd342

1. Download the modified files (thanks Alex!) and unzip > you get a folder named WiFi_kexts
2. Boot into Recovery Mode: restart your computer while pressing and holding cmd-R
3. Open > Utilities > Terminal via Menu Bar (detailed instructions here)
4. Type csrutil disable and hit return
5. Type reboot and hit return > computer reboots normally
6. Open > Utilities > Terminal and enter cd and hit the space bar (don't hit return)
7. Drag the folder WiFi_kexts onto the Terminal window and hit return
8. In Terminal, enter sudo mount -uw / and hit return, then enter your user password and hit return
9. Enter sudo cp -r IO80211Family.kext /System/Library/Extensions/ and hit return
10. Enter sudo cp -r IO80211FamilyV2.kext /System/Library/Extensions/ and hit return
11. Right-click on Kext Utility in the folder WiFi_kexts and choose open, click open in the following dialog, authenticate with your password
12. Wait for Kext Utility to complete – this took maybe two minutes on my setup, and I got an error message in the end, as well as "All done"
13. Reboot your computer and enjoy WiFi in Catalina
14. If you want to turn on SIP again you can boot into recovery mode again and enter csrutil enable (hit return) reboot (hit return)

Files:

https://workupload.com/file/cxdjhdk9BpN

Note this will not work as from Big Sur and beyond see: https://apple.stackexchange.com/questions/372025/missing-wifi-interface-after-upgrade-to-catalina?newreg=1904677ef3d840f0a87b73a2cd7bd342#comment568437_375600

Yes - I have actually replaced the WiFi card on my laptop.

But apparently, Apple has dropped support for the Broadcom card for some stupid reason. Funny enough it is the exact same card that shipped originally with the laptop. There isn't another card that will work with my laptop. The card is good because I tested it by installing Ubuntu, Windows and other Operating Systems on my mac and they all detect the card and have the drivers working out of the box. But Apple in their wisdom decided sadly not to.

Until Catalina, the workaround was to copy over the kernel extension files from an older version of the OS as mentioned in the gist above. Now even that is restricted.

At this point, I found it easier to buy a USB WiFi adapter. You can get one that is very tiny, and you will almost not notice it sticking out of the side.

Good luck.