SAP Note 16174 - Starting up the database: DBA342 and ORA1089

Symptom:

Database cannot be started --> Error messages:
DBA342 unable to complete internal login
ORA1089 immediate shutdown in progress - no operations are permitted
or:
ORA-447, ORA-470, ORA-471, ORA-472, ORA-474, ORA-475, ORA-476, ORA-477

Cause and prerequisites

Shared memory still exists that was not 'cleared out' during the previous shutdown.

Solution
1. Call sqldba
SQLDBA> connect internal
SQLDBA> shutdown abort
SQLDBA> startup