Try using the Override Password Utility on the affected server.
Override Password Utility is a command-line tool used to generate and set the Override Password, but you can also use it to generate an override password hash (the value that gets stored in the registry) so that you can use it elsewhere.
The tool is available via http://www.scorpionsoft.com/downloads/2fa > Maintenance Tools > Override Password Utility
You can test with the following:
- Generate a hash of the override password
- Use the Control Panel tool to set the same override password on that machine
- Compare the registry value with what the tool generated
- Test an override password login