[GUIDE] Dell Precision M6800/M4800 sBIOS mod

derei · Oct 26, 2017

Images in first post missing. Although I can follow the tutorial, I would like to see at least the image with bridging the pins, for permanent unlocking, to make sure I don't do something stupid on my motherboard.

Also, could you recommend a tool for editing the dumped bios file? There are so many available, but I'd like to use one that has been tested and is proven to work, not to create some corrupt file that will brick my bios.

Many thanks!

rzrwolf · Nov 2, 2017

Dear friends.

Can you advise me on my problem?

Maybe the MOD can help me somehow? I have spent like 3 days figuring out the problem with my M6800...

I have version A05 BIOS installed now and it is not updating any further (also no downgrade).

I have tried EVERY version available on DELL support section - from a01 to a19.

Each try just ends in system reboot and usual windows boot with no update.

I have tried installing via DOS usb stick, via various Win versions, via f12 flash upgrade and finally via dell command update program (which suggested to install a19 and asked to reboot - and nothing again)..

A have tried removing all hardware (msata, sata drives, wifi, dvd), tried bios default settings, tried clearing CMOS with battery disconnect.

Thats what i got in log under win update:

***BIOS flash started on 12/13/2013 at 3:27:04***
Command: C:\Users\User\Downloads\M6800A19.exe /s /l=test.txt

A05 INSTALLED (Dell System Precision M6800)
- (NO MANIFEST ON SYSTEM)

A19 UPDATE (Dell System Precision M6800)
- System BIOS : A19
- Embedded Controller : A13
- Gigabit Ethernet : 1.3
- Legacy Video OROM : 2178.V.15
- Legacy RAID OROM : 12.7.0.1936
- Intel Management Engine Update : 9.1.41.3024
- ACPI OS support : 0.0.0.1
- Intel AntiTheft : 3.0.0.18

Exit Code = 2 (Reboot Required)
***BIOS flash finished at 12/13/2013 at 3:27:13***

After reboot - again - nothing.

I just wanted to update to latest version and then mod BIOS, but it looks like i am not getting new version so far..

Can anyone assist? I am willing to pay/donate for help.

rzrwolf · Nov 2, 2017

The thing is - even if i dump my bios - how do i get newer version from DELL packed EXE file?

Or can someone share newer version dump of their BIOS, so i can flash it via mod described above?

rzrwolf · Nov 2, 2017

Thx to valuxin - the problem solved)

belarusian · Nov 9, 2017

Does anyone have an image for pins 1 and 5 of the Realtek audio chip?

valuxin · Nov 10, 2017

@derei @belarusian

Re-uploaded the image with pins in 2nd post of the thread.

derei · Nov 11, 2017

valuxin said: ↑

@derei @belarusian

Re-uploaded the image with pins in 2nd post of the thread.
Click to expand...

Thanks. I was able to unlock my bios and I could see in XTU some extra features (current, turbo boost power time window), but it seems those have no influence. Maybe the motherboard is limiting the current?
Also, how to modify the bios, so I can change the reference clock with XTU?

Thanks.

Blossomcrown · Feb 5, 2018

Hi Valuxin，
thanks for your amazing great work as this guide here
Q1:UPDATED:i've try some work around on M6700 as your method,no surprise that the NVRAM Variables are different.Could you pls point me how to find those thing?i guess i have to analyse the nude BIOS files in some way?
Q2:im also researching the possibility to put a Quadro P5000 in M6700/M6800,it seems like modded version VBIOS OR modded ACPI-DSDT table is required.could you please point me some direction?
Ťhanks very much in advanced!
sry for my bad english

superbug8848 · Feb 10, 2018

Hi Valuxin:
Thanks for your amazing work, I am a new guy for M4800, I want install i7 4980HQ CPU on my M4800( bought it from Taobao, added pins CPU). Now , when I installed the cpu on the mainboard, the notebook can't boot, I think i need add CPU microcode into bios. I already dump the A21 BIOS image, and modified the bios with mmtool aptio 4.50.0.23， add the microcode( CPUID is 00040661, show as 32661), how should I disable BIOS Signing Check feature? Where can I change this setting? Could you please tell me more detail? Thanks.

superbug8848 · Feb 11, 2018

Hi , Valuxin:
I am new for AMI bios mod, you said that after modified the biosbck.bin file, I should disable BIOS Signing Check feature inside the BIOS image , can you tell me more detail , how to disable bios Signing Check feature? Thanks a lot. I want add i7 4980HQ microcode into the BIOS file .Thanks .
valuxin said: ↑
Hi there!

Recently, I found the way to dump, modify and flash system BIOS firmware on Dell Precision M6800/M4800 machines. I'll describe everything in "step-by-step" way. Let's begin.

Introduction
The system BIOS on this machines is AMI Aptio 4.System flash contains the following regions:

Descriptor - contains basic info about flash and permissions. Full access after doing permanent unlock mod. Otherwise, only Read access.

BIOS - contains BIOS itself. Read and Write access.

ME - contains Intel Management Engine Firmware. Read and Write access.

GbE - contains Ethernet info. Read and Write access.

Here you'll find all described and used tools:

FTK - used for dumping and flashing the firmware

Flash Image Tool - utility to modify Descriptor and ME region settings of the firmware and build the final firmware

Clock Commander Tool - utility to operate with Integrated Clock Controller (ICC) of ME engine

!!!All described info is only valid for A16 BIOS!!!
Haven't tested on other versions

STEP 1: Unlock the system features
Firstly, we need to unlock some features to be able to read and flash our roms to sBIOS. For this we need a flash drive formatted in FAT32 and tool from THIS archive - just extract "EFI" folder to the root of you flash drive.

Next, reboot your laptop and boot from this USB stick in UEFI mode - GRUB prompt should appear. Now, we need to change NVRAM variables with "setup_var" command. Here is the list of variables and values:

--SMI Lock, Variable: 0x74
Disabled, Value: 0x00 <<---
Enabled, Value: 0x01

--BIOS Lock, Variable: 0x75
Disabled, Value: 0x00 <<---
Enabled, Value: 0x01

--BIOS Interface Lock, Variable: 0x77
Disabled, Value: 0x00 <<---
Enabled, Value: 0x01

--CFG lock, Variable: 0xC8A
Disabled, Value: 0x00 <<---
Enabled, Value: 0x01

--Mc Lock, Variable: 0xD3F
Disabled, Value: 0x00 <<---
Enabled, Value: 0x01

--VR Current value lock, Variable: 0xC93
Disabled, Value: 0x00 <<---
Enabled, Value: 0x01

--Package power limit lock, Variable: 0xC94
Disabled, Value: 0x00 <<---
Enabled, Value: 0x01

--Overclocking lock, Variable: 0xC95
Disabled, Value: 0x00 <<---
Enabled, Value: 0x01

--Platform power limit lock, Variable: 0x54
Disabled, Value: 0x00 <<---
Enabled, Value: 0x01

--Config TDP LOCK, Variable: 0x3A
Disabled, Value: 0x00 <<---
Enabled, Value: 0x01

--ICC Locks After EOP, Variable: 0xC14
Default, Value: 0x03
All Locked, Value: 0x04
All UnLocked, Value: 0x05 <<---

--Me FW Image Re-Flash, Variable: 0x2BC - this one needs to read and flash ME firmware region. After second reboot, the value will be reset to default 0x00 and you'll loose full access to partition.
Disabled, Value: 0x00
Enabled, Value: 0x01 <<---

Example of usage:
Code:
setup_var Variable - check variable value
setup_var Variable Value - write new value for selected variable
setup_var 0x2BC 0x01 - unlocks ME flash region
After entering all values, command "exit" and press the power button. Changing this vars unlock the BIOS, CPU power management, editing ICC Profiles on the fly, and access to ME region.

P.S. Alternatively, you could place NVRAM editor .efi file at EFI partition of Hard Drive and boot directly from F12 on the go.

STEP 2: Dump the BIOS
After patching NVRAM, boot into Windows and open FTK tool folder. Open spiinfo.bat with Administrative privileges and you should get something like this, saying that BIOS, ME, GbE regions have Read/Write permisions:

View attachment 151545

In this folder you'll find some .bat files that could be used to dump the firmware:

backup.bat - dumps full firmware from the flash to the file backup.bin

biosbck.bat - dumps only BIOS region of firmware to the file biosbck.bin

STEP 3: Firmware editing
After dumping the firmware you could modify BIOS part with your favorite tool. !!!But be careful: for BIOS modification to work, you should disable BIOS Signing Check feature inside the BIOS image - otherwise you'll break the laptop and the only way to restore is via programmer!!! For editing ME firmware settings you'll need full firmware dump and the tool called Flash Image Tool. By this tool you could add the ability to change the Reference Clock via Intel XTU utility.

After modifying, click on "Build" option and you should get outimage.bin in utility folder. Rename it to bios.bin

STEP 4: Flashing the firmware
After committing changes to firmware file you can flash it now. Place your modified bios.bin file to FTK folder and use one of this .bat files to flash wanted region:

biosrefl.bat - re-flashing BIOS region

merefl.bat - re-flashing ME region

gberefl.bat - re-flashing GbE region

After flashing complete - reboot your PC for changes to take effect.

!!!WARNING!!!
!!!Re-flashing with modified firmware may brick your PC!!!
!!!Do it on your own risk!!!

Any help on this project are always welcomed and very appreciated
Click to expand...

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[GUIDE] Dell Precision M6800/M4800 sBIOS mod

derei Notebook Consultant

rzrwolf Notebook Consultant

rzrwolf Notebook Consultant

rzrwolf Notebook Consultant

belarusian Newbie

valuxin Notebook Evangelist

derei Notebook Consultant

Blossomcrown Newbie

superbug8848 Notebook Enthusiast

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[GUIDE] Dell Precision M6800/M4800 sBIOS mod

derei Notebook Consultant

rzrwolf Notebook Consultant

rzrwolf Notebook Consultant

rzrwolf Notebook Consultant

belarusian Newbie

valuxin Notebook Evangelist

derei Notebook Consultant

Blossomcrown Newbie

superbug8848 Notebook Enthusiast

superbug8848 Notebook Enthusiast

Are Dell 7710 and 7760 power bricks interchangeable?

dell precision 7550 screen goes black

Dell really voids warranty if OEM partitions are deleted?

Hp elitebook 8770w vs Dell precision m6800

dell xps 9360 motherboard replacemet from 9350

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