Disable Kext Singing on macOS03 Mar 2017
Since macOS 10.10 Yosemite, Apple featured System Integrity Protection (SIP) in its operating system. SIP is a good thing. It is an extra protection layer which checks if kernel extensions, or kexts, are signed with a developer ID.
Unfortunately, this can break compatibility to some older software. Other reasons for disabling SIP would be the testing of self-written unsinged kexts.
With this command you can disable SIP:
sudo nvram boot-args=kext-dev-mode=1
… and with this one re-enable it again:
sudo nvram -d boot-args