Cold restore of user created dbspace fails

Cold restore of user created dbspace(test dbspace) fails for IDS 12.1. But Restore successful when rootdbs, plog and llog are selected along with testdbs. until 11.5 we were able to cold restore, the physical dbspaces seperatly, ie testdbspace seperatly; then rootdbspace etc. But now there seems a dependency such that the system dbspaces also required to be selected along with testdbspace. I am using onbar for restore. Backup taken was whole with -w option. Similar scenario found in 11.7 also. In that rootdbs, physdbs, tempdbs were required along with test/user dbspace. Any implementation changes? or I am doing anything wrong? I dont see any official docs to confirm this behavior.