Dell XPS 8920 Bios Unlock Primary GPU Selection

[boredofthis]

Bios is an AMI APTIO V bios - I am not sure if that is an issue?
Would love it if someone could unlock the menus for selecting the primary gpu

Bios Revision : 1.0.8
Bios Link : https://downloads.dell.com/FOLDER0442872..._1.0.8.exe (can be extracted with /writeromfile)
Extracted bios (from above link) : https://www.sendspace.com/file/vpk58l
Really appreciate any help with this

Is it possible to unlock the menus for such a bios? I have done a fair amount of reading and I cannot find a clear answer.
Obviously a newbie but would appreciate any pointers.

Am I right in thinking that all I need is MMTOOL_v5.0.0.7 and then I modify the options I want from 'default' to 'user', save and reflash?

thanks.