BIOS_FIRMWARE_TYPE WARNING

Products

• VMware vSphere ESXi

Issue/Introduction

BIOS_FIRMWARE_TYPE WARNING because the servers are running in Legacy Boot mode.

Environment

vSphere ESXi 7.x

vSphere ESXi 8.x

Cause

This is because VMware has deprecated support long term for Legacy BIOS boot.

Resolution

If the host is booting currently, it is ok to leave for now in Legacy Boot.

When ready (before an upgrade or during maintenance) switch the host to UEFI per hardware vendors instructions by changing boot mode to UEFI.

See KB 313152 for details on this process.