Hello
Thank you for posting this issue in the community forum.
Below are some steps you can follow to troubleshoot this Firewire interface issue on Windows 10:
1.Review and Roll Back Problematic Windows Updates: Since your issue appears to have begun after a Windows update, check your update history by navigating to Settings > Update & Security > Windows Update > View update history. If you identify a recent update that correlates with the problem, consider uninstalling it using the Uninstall updates option found in Control Panel > Programs and Features > Installed Updates. For comprehensive information on update history and uninstalling updates, refer to these official Microsoft resources: Windows 10 update history - Microsoft Support and Fix sound or audio problems in Windows - Microsoft Support.
2.Verify and Reinstall the Legacy 1394 Driver: Open Device Manager (press Win+X and select Device Manager), then expand “IEEE 1394 Bus host controllers.” Right-click on your Firewire controller and choose Update driver. Select Browse my computer for drivers and then Let me pick from a list of available drivers on your computer. Choose the 1394 OHCI Compliant Host Controller (Legacy) driver and install it. For detailed instructions on rolling back or reinstalling a driver.
3.Disable Power Management Settings: In Device Manager, right-click your Firewire controller again, select Properties, and navigate to the Power Management tab. Uncheck the option labeled “Allow the computer to turn off this device to save power.” This setting can sometimes cause the device to disconnect after short periods of inactivity.
4.Consider a System Restore: If reinstalling the driver and adjusting power settings do not resolve the issue, you might perform a system restore to a point before the problematic update was applied. You can find guidance on how to use System Restore in Windows 10 here: System Restore - Microsoft Support
Following these steps should help address the intermittent Firewire audio interface problem on your Windows 10 system.
Thank you for your understanding and patience.
Sincerely,
John | Microsoft Community Moderator.