Avoid third-party driver sites. They often package malware or outdated unsigned drivers. The only safe source is the official Cisco Software Download portal.

He found an old bookmark pointing to a decommissioned Cisco support mirror. The link was dead. He tried a cached version of a Russian networking forum. There, buried in a thread from 2022, was a link labeled simply: UPD: ASR9XX_USB_Drivers_Final.zip

Before updating, it's a good idea to check your current driver version. This can typically be done through your device's management interface or by checking the device's documentation.