Have just installed SAT SAMRT driver - Mac won't boot anymore

I have an external drive (USB) for repairing and testing my hardware. It runs El Capitan (macOS 10.11.6) and the latest version of TechTool (12.0.3). I want to check a FireWire drive's SMART status so I installed SAT SAMRT driver. I cannot boot from the USB drive anymore - freeze at black screen with white Apple logo. Why is that? If the SAT SMART driver is not compatible with running from USB start volumes then why was there no warning or something?

Have I to remove the kernel extension or is there any other solution?

Best regards.