How restore SPFILE

RMAN> connect target /

RMAN> set dbid DB_ID

RMAN> startup force nomount

-- Restore spfile to default location (default is for last 7 days)

RMAN> restore spfile from autobackup;

-- Restore spfile to default location (set number of days)

RMAN> restore spfile from autobackup maxdays 20; -- for instance, last 20 days.

-- Restore spfile to other location

RMAN> restore spfile to '/tmp/' from autobackup;

-- Restore spfile to pfile

RMAN> restore spfile to pfile '/tmp/init.ora';