Name: Motorola SURFboard SB5121 USB Cable Modem Driver
Author: Motorola

Question 1

Install fails or driver is unsigned?

Accepted Answer

Run the Motorola installer as Administrator and use Windows compatibility mode. On modern Windows, temporarily disable driver signature enforcement only if the package is trusted and matches your OS.

Question 2

Device not detected?

Accepted Answer

Try a rear USB 2.0 port directly on the PC, not a hub. Power-cycle the SB5121, confirm the coax connection, then check Device Manager for an unknown USB device and reinstall the driver.

Question 3

Version conflicts?

Accepted Answer

Remove old Motorola/SURFboard USB modem drivers and hidden devices in Device Manager, reboot, then install one driver version matching your Windows build.