As is usually the case, the person who runs into this problem tends to be the System Supervisor. So... now what?
Turns out that this is the result of the VM's config file (*.vmx) having a boot order defined. If you've got something like this in your VM's config:
bios.bootOrder = "hdd"
... the BIOS Setup Utility will prevent access to the BIOS screen. Since most of the changes you'd make here are more easily done in the Edit Settings GUI, it's probably not worth it to get access to the BIOS. But if you insist:
- Shut down your VM.
- Edit your VM's .vmx file, and remove to entire line starting with bios.bootOrder.
- Change bios.forceSetupOnce = "FALSE" to "TRUE".
- Save the changes to the config file.
- Start your VM.
Now when your VM starts, it will load the BIOS Setup Utility, and the Boot menu will be editable:
Again, most changes you'll ever want to make to the boot order of a VM can be much more easily done via the VM's Edit Settings screen. But now you know how to change the BIOS Boot settings directly.