Restrictions for changing the firmware/BIOS of certain Virtual Machines

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

Performing an Edit Settings operation to change the firmware of an existing virtual machine, created with hardware version 20 and EFI firmware, would result in a failure when powering on the virtual machine with error message "ACPI motherboard layout requires EFI".

Environment

VMware vSphere ESXi 8.0.x
VMware vSphere ESXi 8.0.1

Cause

Virtual machines with hardware version 20 and EFI firmware are created with ACPI motherboard by default. 
The ACPI layout requires EFI firmware. Changing the firmware to BIOS is not supported in this case.

Resolution

Currently there is no resolution.

Workaround:

If users want to have a virtual machine with BIOS firmware and hardware version 20, they have to create a new virtual machine.