A: According to the VMware Knowledge Base article "Installing ESXi 5.0 best practices," changing the BIOS boot type after installation isn't supported. Per the article, changing the BIOS boot type from Legacy BIOS to UEFI after installing ESXi 5.0 can cause the host to fail to boot with the following error message: "Not a VMware boot bank. Changing the host boot type between legacy BIOS and UEFI is not supported after you install ESXi 5.0."