WYSE Tx0 Configuration

Hello,

Have a wyse tx0 - I do not see how to set a default admin username + password. Seems to me users can just press esc while it boots then configure options.

Am I blind? I can't find any type of user setup on this device.
Is this only grabbed from DHCP/FTP options? If so - still how do we prevent users from pressing esc to get into config mode?

Thanks.