How to define bios.bootDeviceClasses using vmx OR using VM Advance settings

Products

• VMware vSphere ESXi 8.0

Issue/Introduction

The boot device class refers to the type of virtual hardware (e.g., hard disk, CD-ROM, network) from which a virtual machine (VM) or ESXi host attempts to load its operating system or firmware during startup. 

Environment

ESXi 8.x

Resolution

bios.bootDeviceClasses = "allow:all" can be used to return back to default.

Using vmx file:

• Login to the ESXi host where the VM resides. 
• Take a Snapshot of the VM. 
• Edit the vmx using vi editor and add the below entry if it does not exist:
• bios.bootDeviceClasses = "allow:all" 
• Note: Please add this parameter with double quotes. 

Using Advanced Settings:

• Take a Snapshot of the Virtual Machine 
• Right click on the VM and Power Off. 
• Right Click on the VM and go to Edit Settings. 
• Then, click on Advanced Parameters. 
• Select advance parameters bios.bootDeviceClasses = allow:all
• Note: Please do not add this parameter with any quotes. 

 

 

Additional Information

Some additional settings that can be used in the virtual machine's .vmx file:

• bios.bootDeviceClasses = "cd" can be used to force guest to boot from CDROM
• bios.bootDeviceClasses = "net" can be used to force boot from network
• bios.bootDeviceClasses = "fd" can be used to force boot from floppy
• bios.bootDeviceClasses = "hd" can be used to force boot from hard-disk
• bios.bootDeviceClasses = "deny:net" can be used to prevent virtual machines from booting from network
• bios.bootDeviceClasses = "allow:all" can be used to return back to default.

Note: The option sets only the list of allowed device classes and not their order. Therefore, allow:net,cd andallow:cd,net are equivalent.