UEFI version used in VMware virtual machines

Products

• VMware Desktop Hypervisor
• VMware vSphere ESXi

Issue/Introduction

This article provides information about the UEFI version used by VMware virtual machines.

Resolution

The ROM, containing a certain version of the UEFI firmware, is loaded into a VM during the boot process from the ESXi, Workstation or Fusion host.  The ROM will persist in the VM until the next boot, even if the VM is vMotion to a different ESXi host.

For VMs on ESXi, the default version of the UEFI ROM loaded into a VM during the boot process is based on the hardware version of the VM and the version of the ESXi host described in the following table:

ESXi Host	UEFI version
	VM Hardware Version 20 or later	VM Hardware Version 19 through 8
ESXi 8.0 or later	2.7	2.4
ESXi 7.0U3	n/a	2.4
ESXi 7.0U2 - 6.0	n/a	2.3.1
ESXi 5.5 - 5.0	n/a	2.3.0

If the VM is using a vTPM and Secure Boot is not enabled in the firmware, then the ROM from initial boot is carried with VM to new hosts and will be used on all subsequent reboots on different hosts, which may be different than the default UEFI ROM version from the host.

The EFI firmware image carried with the virtual machine will be automatically updated with the image distributed with the current ESXi server when all of the below conditions have been met:

1. The virtual machine guest OS is Windows.
2. It has VMware tools installed.
3. The ESXi distributed EFI firmware image is with greater build number than the one packed with the virtual machine.
4. The virtual machine is restarted on the new ESXi host twice.