(UEFI) Dell XPS 15z L511z modded BIOS - and HOWTO

[jkbuha]

(attachments removed - refer to 1st post!)

Hi all

Apologies for the delay - been travelling back from hols.

I've had some time to apply the changes and work on the modified BIOS, and after some experimentation I am now successfully running an undervolted (0.83V) GT-525 on my Dell 15z A08 BIOS.

CAUTION: THIS MAY NOT WORK FOR YOUR SPECIFIC CONFIGURATION SO YOU HAVE BEEN WARNED!

If you're still keen on trying it out on your 15z (L511z) these are the instructions:

1) On Win32 or Win64 download and extract the attached winflash.rar file
2) Download the modified BIOS file and extract to same folder
3) Drop to a command prompt and run the following:

winflash.exe /BIOS /EC /SA /SV /BBL "BIOS1_GT525M_UV.WPH"

All goes well - you should boot into Windows, and check that the GPU BIOS version has changed to 70.08.56.00.0a. If for some reason the VBIOS is not successful you should still be able to boot with the HD3000 - happened to me a number of times before I worked out the correct way to mod the bios

This worked well for me, but please let us know if you have any successes or otherwise!

Cheers
jkbuha

[jkbuha]

Added GT-540M BIOS mod as well.
I've moved everything up to the first post for all happy (and brave) owners of the 15z to give it a go.

On a related note, if anyone can give me a helping hand to unlocking the BIOS hidden menus it would be much appreciated!

Cheers
jkbuha

[kasar]

nice work, it looks like finally there is a way to mod the bios

since you are the first who posted a fully modded bios with a custom vbios.

happened to me a number of times before I worked out the correct way to mod the bios

can u tell us what steps did u made to mod the modified vbios? so I can start working/tryung stuff at the L502X model

I tried the stuff I posted on the another topic by just modifing a number of the vbios version for testing, but no luck, the card became unusable.

what I was doing wrong?

could you post your phoenixtools.exe configs (if posible on a screenshot like I did on the other forum),also did you used any other app.

I just want to overvolt the card, since I got 0.95v with the stock bios when I play any game,maybe 0.99v would be fine (dont know what is the max voltage supported by the device, or if is posible going to 1.00v or more)

also modding the splash screen would be nice, really bored about DELL XPS's one

[AHMED HOSSAM]

Hi All ,

Great work in the Secure core tiano Platform here from you all , Congratulations

I can help you here with some information now , and with some mods after i finish my final exams in my college .

1 ) In the UEFI platform ( in general ) every module have from 2 to 9 files and every file have some information or checksums while only one holds the required module .
Some explain for this :-
When you searched for the VGA BIOS modules , you may have found 2 or 3 files have the same name and the only difference in names is -0- or -1- or -3- .......... the modules like xxxx-xxxx-[censored]-0.rom , xxxx-xxxx-[censored]-1.rom and xxxx-xxxx-[censored]-2.rom .
you may find the -1- file is bigger ( 64KB ) and holds the VBIOS inside it while the other two files are useless ! ....... No , they arenot useless , they hold the checksum of this module and some other few information but the most important thing is the checksum .
If you tried to replace the VBIOS using andy`s tool , you will find the other two files are changed too ! and if you tried to notice the changes , you will find that only checksum for this module no more is changed .
Andy`s tool automatically adjust checksum in these modules , so no worry about this point ...... its just to knew about these modules .

2 ) You can find several VBIOS modules in the bios but only one needs to be changed :-
This is because that normally the bios is not for only one notebook but its valid for different notebooks which have the same board but different CPUs or VGA cards ......... BIOS detects that VGA and load the right module to it ......... same thing for CPU and others .
So , be sure of the module you are modifying .

3 ) Replacing any module in the UEFI platform is possible like VBIOS , COMPUTRACE , RAID and every thing is possible ........ the only thing we can`t do here is unlocking hidden menus and options no more .
Regarding the progress in this point , We can easily reach the setup module and disassemble it ....... i have done this several times and i`m really near to success in finding menus and unlocking but stopped about a mouth ago due to my exams and study .

4 ) I don`t knew how to mod the VBIOS and only have some information about this , so i can`t help in modifying the VBIOS but for replacing its module , i have explained this in point 1 ................ if i knew how to mod it , i would have modified my own old ATI4570 VGA

EDIT : don`t use any backup images for the bios to modify , it can`t be flashed after modified as it doesn`t have the platform information which is important for the phlash tool .
Just use the original bios from the manufacturer website .


I haven`t logged into the forum for 2 weeks before today due to my study , so don`t expect fast reply from me and be patient
i promise i will do more progress in unlocking menus when i got time to do this after finishing my exams .
I don`t knew if i missed something important here to say but I`m Glad to see this progress here and feel free to ask any questions

Thank you ,
Ahmed

[kasar]

oh, the checksum thing, so my suspects about it were right!

thank you a lot AHMED, thanks to your post, now I understand more stuff and I know that I will need to find and download andy's tool to get rid of the issues I got due a modified file without modifing the checksum.

now I would like to ask you if you can help me relating two things:

one of them is to make sure about a way to resurrect my laptop in case of bios flashing failure, I made a usb recovery stick with some things I found for phoenix bios, but I'm not sure if will work for my laptop, if I plug the usb disk in, press fn+b or fn+f before/while the system boots, it enter in some kind of disagnosis mode, but didnt asked me to flash any bios, that is why I'm worried.

my bios type is securecore tiano
I heard somewhere them are able to preserve at least a part of the code so they are never fully bricked, but not sure, also not sure if I made the correct method for the recovery usb stick, I just want to make sure, in case of a bad flash, I will be able to flash/restore the original bios, using the usb stick or something else.

the another thing is about the splash image, i want to modify the one from dell with a custom image.

I think I found the module for the image, but no image software were able to open it, except one wich were able to show a part of it.

I uploaded the mentionated module with all the related files, including the 1kb files suposing to be the checksum or aditional info.
I were focusing on the 0C7F41A9-0A6F-43F6-A0D9-1E2D01DBD7BE_4_1122.rom file

thanks for your help in advance

PS: nice avatar from "the last samurai" film

[AHMED HOSSAM]

How did it enter in some kind of disagnosis mode !
In the recovery mode , you should see black screen and the usb drive LED turning on and off ( the USB flash drive which have the recovery files ) .
and after 10 minutes the notebook restarts automatically with the original bios which was flashed using recovery method .
To make sure its working for you ,
1 ) flash the original bios file from windows normally ....... then you will see that the vga is back to original too .
2 ) use your recovery method with your modified bio file and after its finished , see if it has changed the vga ....... if yes , then its working perfectly .

As far as i knew , the recovery for the TIANO UEFI require some special files which are not available now .
and yes you are right , the boot block inside the bios has got a routine for recovery ........... once you put the flash drive with the recovery files and triggred the correct key comibnation then it works .

Concerning the logo module you have attached :-
the 0C7F41A9-0A6F-43F6-A0D9-1E2D01DBD7BE_4_1122.rom file is the logo
while the 0C7F41A9-0A6F-43F6-A0D9-1E2D01DBD7BE_1_1122.rom file ( if opened with hex editor ) you will notice its a DLL file which seems to operate something .
the other modules holds few information and the checksum .
I haven`t modified a BIOS logo before ........ i knew its easy but i was just interested in unlocking options and researching the BIOS structure ........... so i`m not sure i can mod it but i will look into it later as i haven`t alot of time these days .

I adore this movie ( The last samurai ) , i watched it several times

[kasar]

thanks for your fast answer

as I suposed the recovery method I tried may not be usefull at all since it doesnt flash anything. I placed also a file I found at the usb stick root folder, te file I found were at dell update bios winflash folder named recovery.fd (2mb) .
copied it renamed as some names I read on some forums it would work, maybe the recovery mode just trigger by automatic if the recovery rountime dont detect a working bios. not sure anyway

however since you said the required files for tiano are not avalible yet,I supose I will be definitly screwed if the flashing goes wrong, being unable to resurrect the laptop since there are no verified methods yet to revive it

this worried me a little about keep trying to flash test/modified bios.

however since I was at least being able to modify the setup app bios tittle by hex editing I think I am close enough to flash a modded vbios module and custom splash screen.

am I brave? or just mad? I dont know , you decide, lol

well,could you tell me more about the checksum fixing after modifiyng the modules?
specially where to get the required tools, and the procedure, at least a little/small overview.

I read about you use andy's tools, but didnt found so much files on the net with that name, I 'm using now phoenixtool.exe (phoenixdell/efi Slic v1.93)

i use it to dissasemble and assemble the bios after modify modules

modifing text on the bios setup app worked for me, have a current moded bios with my name on it, but the vbios modification didnt worked, I suspect it is related the checksum, since the nvidia card refuses to work with the drivers after the mod, (glad I still able to see the screen thanks to the intel HD3000)

yep, the last samurai is a good film for sure

[jkbuha]

nice work, it looks like finally there is a way to mod the bios

can u tell us what steps did u made to mod the modified vbios? so I can start working/tryung stuff at the L502X model

I tried the stuff I posted on the another topic by just modifing a number of the vbios version for testing, but no luck, the card became unusable.

what I was doing wrong?

could you post your phoenixtools.exe configs (if posible on a screenshot like I did on the other forum),also did you used any other app.

I just want to overvolt the card, since I got 0.95v with the stock bios when I play any game,maybe 0.99v would be fine (dont know what is the max voltage supported by the device, or if is posible going to 1.00v or more)

also modding the splash screen would be nice, really bored about DELL XPS's one

Here is the reason why. After repeated attempts - all unsuccessful - to make a custom VBIOS I realised that the last byte of the NVIDIA VBIOS files is a checksum byte as well. So basically if we change any byte in the file, the last byte needs to be correctly checksummed as well, otherwise the BIOS will not load. And we don't know how to calculate it for now. So the only way - for the moment - to mod our GPU is to use an existing file.

So kasar - if you use any of my uploaded VBIOS files as-is without modification - they will work because the checksum byte at the end of the file is correct. Until we figure out how this is calculated it seems that this is the only way to mod our GPUS

@Ahmed - great to have you back! I had my doctorate viva exams this summer as well so I know what it feels like to be under pressure! Best of luck for your final exams and hope they bring you all the success and fulfilment you have been looking for! Any pointers you can give me to look out for unlocking the menus will be much appreciated.

I'm travelling again for holidays over the next few days so will have limited access but will be checking this forum regularly. In the meantime best festive wishes to all

Cheers
jkbuha

[kasar]

Here is the reason why. After repeated attempts - all unsuccessful - to make a custom VBIOS I realised that the last byte of the NVIDIA VBIOS files is a checksum byte as well. So basically if we change any byte in the file, the last byte needs to be correctly checksummed as well, otherwise the BIOS will not load. And we don't know how to calculate it for now. So the only way - for the moment - to mod our GPU is to use an existing file.

So kasar - if you use any of my uploaded VBIOS files as-is without modification - they will work because the checksum byte at the end of the file is correct. Until we figure out how this is calculated it seems that this is the only way to mod our GPUS

thanks for the info jkbuha

so, as far I understand, there is more than 1 vbios checksum, one is stored a the small files ahmed mentioned, and the another is inside the vbios itself , am I wrong?

I supose getting a modified vbios working require getting both checksum OK

else I will get the same Issues I had on the another forum after flashing the modified vbios


I
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relating what did you say, I already tried when I testing tons of stuff, or at least tried flashing the vbios posted at following link without modify them.

http://forums.guru3d.com/showthread.php?p=4196795

are those the same ones are you using on your custom bios?

if not, can you upload them or provide me the url from the site you got them?


edit: I'm testing now to load the vbios file with nbitor 6.03, it seems to help a bit while modifing the vbios, or at least it provide usefull information like 61 was the default checksum on my file.

thanks in advance, oh, just forgot to say :
my best festive wishes to all , we are almost at the next year

[AHMED HOSSAM]

Thank you i hope you all success in your exams too

Andys tool is the phoenix tool which you all using now , no problem about this .
every module like setup orraid or even vbios has a checksum inside the module file itself and should be modified to let the module works well
Its an 8bit checksum ,,,,,,, some hex editors automatically dectes the 8bit checksum of the file and you should do this :-
--- download a tool called. Chk8 ( 8Bit checksum calcuator tool ) and after modifying your vbios , check the new checksum and modify the old one .

This totally differs from the checksum inside the other file i told you about in my previous replies ,,,,,,,,,,, for now , there are 2 checksum
One inside the module itself and its 8bit checksum and should be manually modified .
The other is for the compressed module ( the module is usualy compressed but the tool extracts it to modify , the bios includes checksum for the compressed file and this checksum is written outside the module ,,,,,, while the original uncompressed modile includes its own checksum )
The other checksum is automatically modified by the tool while you should modify the first one .
I'm using mobile now and will explain more after i go home .
Thank you,
Ahmed