I have to downgrade my test database from to
I have backup of database from release ( before upgrade on,and backup of controlfile,spfile,listener.ora,tnsnames.ora and pwd file.Database is in noarchivelog mode.

What is the most easy way of downgrade?

I thought:
1) Drop database and unistall oracle
2) Recreating of instance
3) With RMAN,restore controlfiles and datafiles ( but I realised that i have to do recover database,but with drop database I lose all logs).