USB 3.0 on 17" MacBook Pro under El Capitan - Thu, Jan 21, 2016
I had added USB 3.0 functionality (via a GMYLE BC628) to my Late 2011 17" MBP as per my earlier post. Mac OS X 10.11 El Capitan introduced a new layer of security that prevented my previous configuration from working.
Fortunately, others have figured out a road back.
Here are the steps: Backup everything and assume you’re about to trash your system. I am not responsible for what happens here. Boot in to your recovery partition, or on to a USB installer Execute:sudo csrutil disable kext. This disables kext signing. Boot back to your native system. (Note USB-booted environments probably don’t need the sudo component.) Download GenericUSBXHCI.kext to your Desktop Run KextBeast, install to /Library/Extensions Reboot Profit!
References: General process Generic USB Kext