Hello everyone - Since the creation of this thread I have waited 9 months to tell you the following:
STOP PRESS WE HAVE NOW ENABLED ALL HIDDEN MENUS ON THE XPS 15Z (L511Z)!
LATEST A11 BIOS IS COMPLETELY OPEN WITH ALL OPTIONS ENABLED!
All menus are now available including UEFI Boot, Graphics Card selection, overclocking/volting and much much more! There's sooo many options I'm not even sure as what to modify
HACK HOWTO:
The irony of course being that we just needed to change one byte, offset 31BC9 in 15z A11 Bios, from 00 to 01.
I'll be back in a while to tell you how to do it on your own machines, including credits to who helped me massively in this, and upload the 15z modded bios to this thread, but for the time being try and see if you have the following byte sequence in your XPS 15 / 15z BIOS:
1) Find your AdvancedSetup efi module
2) offset 0031BC0: 00 29 02 29 02 0A 82 45 8A (00) <- change to 01
3) re-pack with phoenix tool and good luck!
Please report if (i) you manage to find this byte sequence, and (ii) if you do - if you enable all menus!
We'll be doing a post-analysis (how and why) very soon!
Here's to a new chapter for unlocked PhoenixDell UEFI Bioses!