The Quick Boot of ESXi hosts is an option that allows Update Manager to reduce the time a host remediation takes by skipping the physical reboot of the host.

Using Quick Boot is supported with a limited set of hardware platforms, drivers, and is not supported on ESXi hosts that use TPM or passthru devices. For more information about a host compatibility to Quick Boot option, see the following KB Article:

The option to enable Quick Boot is available in both the vSphere Web Client and the vSphere Client.