Follow these steps for Airdrop activation. However, search the thread for your machine specific ktext files.
REPEAT PLEASE LOCATE ZIP FILE TO YOUR MACHINE SPECIFIC ON THIS THREAD.
The zip file posted is for MacBook Air 4.2 ( 2011 ) You should locate for your model.
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AirDrop Catalina pre-patched (only for Broadcom cards) to those interested you should post the output of these Catalina Terminal commands:
ioreg -l | grep "board-id" | awk '{print $4}'
ioreg -r -n ARPT | grep IOName
system_profiler -detailLevel mini | grep "Card Type"
system_profiler -detailLevel basic | grep "Model Identifier"
Meanwhile here are some Wifi kext that I've pre-patched (tested and working) to AirDrop on Catalina unsupported Mac, they are hyperlinks so just click the one for your machine to download:
AirDrop Catalina patched MacBookAir2011 4,2.zip
After downloaded, open a Catalina terminal and copy/paste:
sudo mount -uw / ; killall Finder
Then from Catalina Finder replace (do not merge) them inside your Catalina /System/Library/Extensions/
after from a Catalina terminal send these commands copy/paste one at once:
sudo chown -R 0:0 /S*/L*/E*/
sudo chmod -R 755 /S*/L*/E*/
sudo kextcache -i /
(the "kextcache" takes some minutes to complete)
At next reboot you should have AirDrop in Catalina Finder.
After you have a working AirDrop, I suggest to apply this additional fix to enable an extra AirDrop feature that apple removed from Catalina:
"AirDrop Search for older Mac"
After a working AirDrop on Catalina, if you have also a Bluetooth 4.0 card (or BT4.0 usb dongle), to add Continuity (Handoff, hotspot, etc.) check this example:
enable continuity from terminal
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Above was posted by many genius good people who have contributed to having unsupported Macs work with Catalina.
