MDT Database Permissions

The user account used for connecting to MDT must have access to the MDT database. Use SQL Management Studio Express to grant permission.
Edit bootstrap.ini with the following options to completely automate the processes:

[Default]
UserID=UserAccount
UserDomain=DomainName
UserPassword=Password123
SkipBDDWelcome=YES
DeployRoot=\\Server\Share

References:

http://windowsdeployments.net/installing-the-mdt-database-with-windows-adk/
http://www.toddlamothe.com/deployment/customizing-bootstrap-mdt.htm