Kenneth Igiri walks us through restoring the master database in SQL Server:
The master database contains records of the structure/configuration for both the current instance and all other databases. When you run sp_configure, you are writing data to the master database. It also contains most of the dynamic management views that are necessary to monitor the instance.
The importance of the master database is crucial. First, it has the information necessary for opening all other databases and has to be opened first. Then, it involves all instance level principals for the current instance.
It is crucial to back up the master database daily. Equally important is to know how to restore the master database to the instance. The most frequent cases are the database crash or the necessity to restore the master database to another instance when no longer use the source instance. In this article, we will examine the specific case of moving the master database to another instance.
It’s definitely not as easy as restoring other databases, but it is possible.