Unauthorized BIOS modifications in arcade machines can lead to hardware malfunctions, cheating, or even revenue loss for operators. To safeguard these systems, consider the following effective strategies:

1. Physical Security Measures: Secure arcade machines in locked cabinets or enclosures to prevent tampering. Use tamper-evident seals on critical components like BIOS chips.

2. BIOS Password Protection: Set strong BIOS passwords to restrict access. Ensure passwords are unique and changed periodically to minimize breaches.

3. Firmware Signing and Encryption: Implement signed firmware updates to verify authenticity. Encryption adds an extra layer of protection against unauthorized changes.

4. Regular Firmware Updates: Keep BIOS firmware up-to-date with patches from manufacturers to address vulnerabilities.

5. Monitoring and Logging: Deploy monitoring tools to detect unauthorized access attempts. Maintain logs for auditing and identifying suspicious activities.

6. Disable Unnecessary Ports: Disable USB or other external ports that could be used to inject malicious firmware.

By combining these methods, arcade operators can significantly reduce the risk of unauthorized BIOS modifications, ensuring fair play and system longevity.