Dell XPS 15/15z L502x/L511z BIOS MOD HOWTO

Discussion in 'BIOS Mods' started by jkbuha, Dec 25, 2011.

  1. jkbuha

    jkbuha MDL Novice

    Nov 10, 2011
    #1 jkbuha, Dec 25, 2011
    Last edited: Dec 25, 2011
    Hi all

    This is my first go at a BIOS mod, and I'd just like to double check a few steps to ensure I'm doing everything before I take the plunge and pflash.exe the ROM .... :)

    So here goes:

    Objective: To mod existing DELL XPS 15/15z BIOS (UEFI Tiano) for either of the following options:
    1) Change existing Video ROM to an undervolted ROM, or mod the Nvidia 525M to a 540/550M by replacing VBIOS
    2) Unlock Hidden Options in BIOS

    1) Obtain the following tools: i) Universal BIOS Backup Toolkit v2 ii) PhoenixDell EFI SLIC MOD v1.93
    2) Under Windows, run Universal BIOS Backup and save your existing BIOS to a ROM file (my Dell XPS 15z A08 BIOS saved as DellInc.-A08.ROM
    3) Run PhoenixDell EFI tool, select above ROM file, and wait for all modules to be extracted
    4) Do a HEX search to find the desired files in the DUMP folder to view/patch. In my case I was looking for my VBIOS, so I searched for NVIDIA and voila! my VBIOS rom appears in the file 8C8BAE9C-4AEB-44DF-AB67-1E4D8242E964_1_813.ROM
    5) Select Advanced in PhoenixDell Tool, and tick the modification options under Control Options. That way when you patch your required file the packer will pause to allow you to make the modifications. I also selected 'NO SLIC' as my BIOS already has 2.1. Apparently.
    6) Click Done, and then Go. Replace and/or patch existing file as required when prompted, and click ok when done.
    7) PhoenixDell should identify the patched file and ask whether you want to include this newer file. Select yes
    8) A few more writes later, and voila! New patched DellInc.-A08_SLIC.ROM file

    So far so good. Now I have a few questions myself:

    1) How do I flash this file (pflash?) and is the above method correct - my patched ROM file is approx 2.5MB and the original WPH file was about 5MB?

    2) Where should I go snooping about to unlock all the hidden BIOS options in this ROM file?

    3) If Murphy's law prevails and I end up with a wrongly flashed BIOS, how do I recover? :)

    Thanks to all for the great contributions on this forum - it's thanks to your input I have managed to get this far!