VMware: How to rollback ESXi 5.1 to 5.0

Whenever you find issues after upgrading  to esxi 5.1 from 5.0 , rollback is as simple as below.

Reboot the host and press R to start the Recovery Mode..

Installed hypervisors:
HYPERVISOR1: 5.0.0-623860
HYPERVISOR2: 5.1.0-799733 (Default)
CURRENT DEFAULT HYPERVISOR WILL BE REPLACED PERMANENTLY
DO YOU REALLY WANT TO ROLL BACK?

Press Y to start the roll back



Result:

The host is downgraded and back online again with VMware vSphere ESXi 5.0.0