Shawn Melton shows us how to modify SQL Server startup parameters using Powershell:
Low and behold the StartupParameters property is one that can be read and set. So how do you set it? Well the one thing to remember is you DO NOT need to remove what is already in that property because IT WILL BREAK YOUR SERVER!
Let me be clear, setting the property means you need to append to what is already there, so don’t just go setting it equal to something like “-T1118”. Doing this will remove the required parameters to start SQL Server itself, and no it will never warn you of this…so proceed at your own risk.
Read the instructions; otherwise, you can mess up your installation, and that’d be a bad thing.