According to this new KB article there’s a backdoor for ESX3i:
- Log in to your ESX Server 3i at the console.
- Press Alt+F1 to switch to the console window.
- Enter unsupported to start the Tech Support Mode login process. Note that no text will appear on the console window.
- Enter the password for the root user. Tech Support Mode is now active.
- Complete tasks in Tech Support Mode.
- Enter the command exit to exit Tech Support Mode.
- Press Alt+F2 to return the server to DCUI mode.
For more info check the KB article. I will be checking out this feature over the next couple of days to see what’s possible in this mode.