Rollback ESXi 5.x Upgrade or Reverting to a previous version of ESXi

To revert to a previous version of ESXi after upgrade:

1). From the Console screen press F2
2). Then press F12 to see the shutdown options for your ESXi.
3). Press F11 to reboot.
4). When the Hypervisor progress bar starts loading, press Shift+R.
5). Now you will see a warning message:

Current hypervisor will permanently be replaced
with build: X.X.X-XXXXXX. Are you sure? [Y/n]

6). Press Shift+Y to roll back the ESXi to previous version.
7). Press Enter to boot in to the selected ESXi version.