I wanted to revert back to El Capitan from Sierra because of some keyboard issues and I wanted to use a different HDD. I installed the HDD I wanted to use and did an internet recovery mode. Used a Time machine backup to reinstall the boot drive. I need to disable SIP to install the HDMIAudio kext but it won't boot to any recovery mode. I did try resetting the NVRAM, opt-cmd-P-R. That did not help. I have tried to download the installer from the App store but it won't let me. How can I get this into recovery mode? Where would I look and what would the installer be named in my Time machine backup? I am using a MacPro 5,1.