I recently upgraded a client’s ConfigMgr 2012 environment from RTM to SP1.  During the upgrade it’s recommended that you make a copy of the ConfigMgr database and restore it using a different name then test the upgrade using the /testdbupgrade command line with setup.  We moved the database to not only another instance but another sql server.  During the testdbupgrade we were getting errors.  looking at the log setup was trying to connect to the production sql server using the instance name and db name we specified in the command line.  It was not trying to connect to the different TEST server re restored the db to.  I found a blog by Aaron Czechowski that explained an undocumented command line that tells setup to use another server ( setup.exe /testdbupgrade DBName /testsqlserver VirtSqlSrv ).  Using that info we were able to connect to the test server and test upgrading the db.  Thanks Aaron. 

 

Microsoft’s documented command line options for ConfigMgr setup.