Locate CDM Install Folder

• Open FireFox
• Click the Menu

• Click Help
• Click More troubleshooting information
• Locate the Profile Folder section
• Click Open Folder

• Click Open file location, This will open Windows Explorer
• Close FireFox
• Navigate to gmp-widevinecdm
• Navigate to the 4.10.xxxx.x folder

Overwrite CDM

• Download Widevine CDM 2209: https://dl.google.com/edgedl/widevine-cdm/4.10.2209.0-win-x64.zip
• Copy and replace the following files:
  • widevinecdm.dll
  • widevinecdm.dll.lib
  • widevinecdm.dll.sig
• You can now open FireFox

Note: Don't replace the manifest.json file as this will cause FireFox to update the CDM