If were referring to other devices, yes - Implement BIOS passwords before they are compromised. But the ones that were already compromised, they need to be removed from the system to avoid further exploitation. Plus, if you put a password on there, the attacker may now have your password.
Remove the assets from the production network for analysis. If the analyst receives an alert about unauthorized changes to the firmware versions on several field devices, the best action to recommend to the asset owners is to remove the assets from the production network for analysis. This would prevent further exploitation of the devices by isolating them from potential attackers and allow the analyst to investigate the source and nature of the unauthorized changes. Changing the passwords on the devices, implementing BIOS passwords, or reporting the findings to the threat intel community are other possible actions, but they are not as effective or urgent as removing the assets from the production network for analysis. Reference: https://www.sans.org/reading-room/whitepapers/incident/incident-handlers-handbook-33901