In a default configuration, all DCUs are assigned to /HOST0, and SPP0 is assigned to /HOST0, with all other SPPs set to standby for failover. If you perform a system firmware upgrade in nonpreserve mode (invoking a fallback to the default configuration) and after which a failover from SPP0 occurs, you might be unable to start /HOST0.
Workaround: Start /HOST0 with the –f option. For example:
-> start -f /Servers/PDomains/PDomain_0/HOST