My fork of soundflower with some personal tweaks.

How to build

Disable System Integrity Protection. Reset to recovery (hold Command+R while loading). Menu -> Utilities -> Terminal:

csrutil disable

Then reboot, go to console. Allow loading kext from any location:

systemextensionsctl developer on

Unload and remove old build (if any)

sudo kextload -v /tmp/Soundflower.kext
sudo rm -R /tmp/Soundflower.kext

Copy and load new one

sudo cp -R Build/InstallerRoot/Library/Extensions/Soundflower.kext /tmp
sudo kextload -v /tmp/Soundflower.kext

Mount / in RW-mode

sudo spctl --master-disable

sudo mount -uw
sudo killall Finder

Copy to /System/Library/Extensions (NOT UNDER MC!)

sudo cp -r /tmp/Soundflower.kext /Library/Extensions

Reboot? Profit!

Show kernel logs (useful to see CoreAudio output):

log stream --process 0

IOLog. For some reason messages are corrupted :(

log show --predicate 'senderImagePath CONTAINS "Soundflower"'