Looking for help creating/modifying a script to update/repair agents that can be deployed via group policy

Ideally looking for something to launch at startup/shutdown to update/repair agents that can't be reached via console. Agents that have failed to upgrade automatically would benefit from being repaired/upgraded via script deployed via group policy, 

currently an official script released for installing agents, but would be ideal if it would include repair options if needed. 

Hit a dead-end with paid support, would appreciate official support in this task.