Oracke RMAN: Recover DB when backup folder has changed
The entries of backup pieces are still pointing to /xxx/yyyy in the controlfile.

After you reach MOUNT stage, catalog the backup pieces from their new location. In RMAN:

catalog start with '/aaa/bbb';


After this, continue as you normally would.

Update:

For 9i, the above is not possible, there is no such option in 9i, you can not catalog backup pieces, this feature was added in 10g. The solution is in the below note:

how to restore or clone a 9i database to different host when backup location is different (Doc ID 1451140.1)

It suggests mounting the database (controlfile) with a 10g software, use the above catalog command, then shut down the instance, and continue with the 9i software.

I think it is easier to create a symlink /xxx/yyyy pointing to /aaa/bbb.