[Help] Bricked BIOS DellPrecision 7520. Help needed for recovery

Update: Bios boots to SetupMenu, but Intel ME disappeared.
Help needed for UEFItool

Dear all, after disk wipe in BIOS, seems also BIOS content got corrupted.
(Lesson learned: never wipe M.2 or SSD from BIOS…)

After Dell logo, the laptop hangs. If I press F2 or F12, up right appears a similar text
‘preparing to enter setup’, and boot process hangs again.

I tried BIOS recovering with USB + holding Ctrl+ESC keys.
The BIOS reads BIOS_IMG.rcv from USB, did some Bios + ME flash updates and rebooted.
But after the recovery/update, boot process hanged again

I tried also entering diagnostic menu by Holding Fn key, also hangs.

What I did:

  1. Dumped the 16Mb SPI flash chip to file, using SOC-8 clamp and application flashrom
    Files are in the archive, see links below
    dell-precision-7520-chipW25Q128xV.bin
    MD5: 9854d24a7461afdd64f41fca20c7ba34

  2. Downloaded last bios from
    BIOS Dell Precision 7520 and 7720 system-BIOS
    h_t_t_p_s://w_w_w.dell.com/support/home/nl-be/drivers/driversdetails?driverid=6h1vv

Precision_7x20_1.23.1.exe 13.34 MB
MD5: 2afaeb7dfe5896adc46b312ef8e3b05d

BIOS Recovery Image File
BIOS_IMG.rcv 13.33 MB
MD5: 4691e476f07db54e761bca56cd8e6c79

The BIOS .exe was extracted to Precision_7x20_1.23.1.exe_decompressed.hdr size 17237498
MD5: e905ab334e8ceb953637b10c6c38299a

and using PFSExtractor, I got such a directory, also in the zip archive:

ls -lA Precision_7x20_1.23.1.exe_decompressed.hdr.extracted | cut -f5- -d’ ’

9601985 May 26 01:25 section_0_1.23.1.data
300 May 26 01:25 section_0_1.23.1.meta
256 May 26 01:25 section_0_1.23.1.mtsg
9437184 May 26 01:25 section_0_1.23.1.payload
256 May 26 01:25 section_0_1.23.1.sign

I tried dumping my dump file dell-precision-7520-chipW25Q128xV.bin,
some files extraction failed because of bad/missing ‘huffying table’ file

UEFITool detects it as Intel image, I see the MAC in GbE region

So I am stuck to this point :frowning:
I have no clue how to proceed further. I suspect I need the laptop-specific
info (MAC,serial…) merged to the .hdr file above, and finally to
create a 16Mb image, that I can write back to SPI chip.

I’ll be very happy if somebody can merge a working binary from my dump
and the downloaded .exe binaries
:slight_smile:

Also, I’ll highly appreciate if Intel AMT/ME functionality is enabled. I think
it was enabled, not sure

Thanks,
Jan

53Mb zip archive with binaries

Will expire on 25Jun2022:

or
_h_t_t_p_s://www.sendspace.com/file/jpf4qu

p.p. Some links
_h_t_t_p_s://www.sentinelone.com/labs/moving-from-manual-reverse-engineering-of-uefi-modules-to-dynamic-emulation-of-uefi-firmware/

_h_t_t_p_s://nstarke.github.io/firmware/uefi/ru.efi/bios/2020/08/01/modifying-bios-using-ru-efi.html

_h_t_t_p_s://phreesite.com/free-anonymous-file-sharing-sites-without-registration/

1 Like

Is it New Issue or Old I am going to edit it for you for FREE. Try TO remember (Pk4Tech). First inform me is it done or not…

Check, I have Cleaned Me and Bios Region as it is link: Upload files for free - Pk4Tech dell-precision-7520-chipW25Q128xV Me Clean & Bios Resion New .bin - ufile.io


Check This out Your File & My Edit

Great !

Will upload it (slooow…), assemble the laptop and try

Is Intel AMT ME still active ?
So that I can do the initial setup with admin/admin … ?

Check My Complete Edit File with full Setup Password: Pk4Tech
link:Upload files for free - dell-prec-7520-bricked.rar - ufile.io

1 Like

Thanks
My linux unrar cannot extract with pass … checking it

EDIT: Partial success

  • booting to F2 / setup menu works; I was able to run again BIOS update with Precision_7x20_1.23.1.exe
    from USB
  • Intel ME / AMT does not work. In F2 / Setup menu is available ‘Ctrl+P/F12’ for ME engine,
    but not available in F10 boot menu, or pressing Ctrl+P. I suspect Intel ME got disabled somewhere

Anyway, thanks :champagne: :+1:

EDIT2: Installed Debian +XFCE to M.2nvme, OS boots ok
Still no Intel ME functionality

1 Like

AMT wasn’t enabled in the dump you posted?

Otherwise: Which file did you flash? One had jyst a stock bios and the other version had a stock bios and a cleaned/ reinitialized ME (but still all without AMT enabled)

In addition the DVAR section is missing in stock image, might get recreated, but du you still have service tag, serial…?

Hi lfb6,
In my first post, there is a link to 53 Mb archive, I think you already downloaded and opened it

Next, Pk4Tech was so kind to fix it,

and I programmed his image to the SPI chip here. The Bios setup menu appeared, and inside I see
‘Enable PEBx Ctrl+P/F10’ not-grayed out item
It is checked/selected

But no Intel ME …

Anyway, is it possible to enable/merge ME functionality in my file ?
It was partially damaged, seems Huffman.dat or something similar was missing.

I’ll be very happy if you can fix it, or direct me to some useful pages @ this great site
I am long time linux user, no problem to build / troubeshoot :wink:

Cheers
Jan

EDIT
I suppose this info is available in my archive in first post ?
If not: service tag J3730N2
Expess Service Code 41552161022

lfb6:
In addition the DVAR section is missing in stock image, might get recreated, but du you still have service tag, serial…?

Well, you’re mixing things here. ME is not AMT or vpro. The ME is always running and there’s for the moment no reason to believe that the ME it’s not OK. For AMT/vpro you need a vpro capable chipset, processor and network card. And as written there’s no sign that these ME functions were enabled anytime before.

In the 53 MB archive there’s a valid dump with checksum file and some schematics, the other tries to unpack a stock bios aren’t very useful. What are you refering to?

Download CSME System Tools v11 r45 from
ht tps://winraid.level1techs.com/t/intel-converged-security-management-engine-drivers-firmware-and-tools/30719
and run MEInfo. Post / attach the result.

DVAR region is where Dell stores it’s variables like serial, service tag, OEM Windows license. There might be other places not in the firmware where this information could be kept (TPM for example) so if everything is still showing up in the bios this might be OK.

L > Well, you’re mixing things here. ME is not AMT or vpro. The ME is always running and there’s for the moment no reason to believe that the ME it’s not OK. For AMT/vpro you need a vpro capable chipset, processor and network card. And as written there’s no sign that these ME functions were enabled anytime before.

Indeed, thanks for clarification
I need Intel AMT, if vPro is also available … great

L > In the 53 MB archive there’s a valid dump with checksum file and some schematics, the other tries to unpack a stock bios aren’t very useful. What are you refering to?

Yes, the file with checksum is the dump of my original damaged BIOS
You can ignore the stock BIOS, I was hoping some good pieces can be reused

L > Download CSME System Tools v11 r45 from
ht tps://winraid.level1techs.com/t/intel-converged-security-management-engine-drivers-firmware-and-tools/30719
and run MEInfo. Post / attach the result.

I have no Windows machine right now, only linux … This is link with output
of MEAnalyzer command: ./MEA -skip -ver86 -unp86 -html dell-precision-7520-chipW25Q128xV.bin
of my SPI dump: h_t_tps://ufile.io/wfeyvttn

L > DVAR region is where Dell stores it’s variables like serial, service tag, OEM Windows license. There might be other places not in the firmware where this information could be kept (TPM for example) so if everything is still showing up in the bios this might be OK.

Yes, this info seems still available and intact.

Cheers,

MEInfo exists in Linux version, you run it on the working machine. Even without Linux version it wouldn’t be too hard to create a DOS USB stick for example.

Hi lfb6,
Here is link to DOS MEinfo output: Upload files for free - log-meinfo-dell-prec-7520.txt - ufile.io

I found in user manual of Precision7520, my processor i7-7820HQ supports
“Intel vPro technologie (i5/i7) met Active Management Technology 11.6”

Have a nice day,

>  CurrentState:                               Normal
>   ManufacturingMode:                          Disabled
>   FlashPartition:                             Valid
>   OperationalState:                           CM0 with UMA
>   InitComplete:                               Complete
>   BUPLoadState:                               Success
>   ErrorCode:                                  No Error
>   ModeOfOperation:                            Normal
>   SPI Flash Log:                              Not Present
>   FPF HW Source value:                        Original FPF HW Fuse Bank
>   ME FPF Fusing Patch Status:                 ME FPF Fusing patch NOT required
>   Phase:                                      Maestro
>   ICC:                                        Valid OEM data, ICC programmed
>   ME File System Corrupted:                   No
>   FPF and ME Config Status:                   Match
> .........
> Found an Intel vPro Wireless device
> ........
> FW Capabilities                              0x31111140
>                                              
> 	Intel(R) Capability Licensing Service - PRESENT/ENABLED
> 	Protect Audio Video Path - PRESENT/ENABLED
> 	Intel(R) Dynamic Application Loader - PRESENT/ENABLED
> 	Service Advertisement & Discovery - NOT PRESENT
> 	Intel(R) NFC Capabilities - NOT PRESENT
> 	Intel(R) Platform Trust Technology - PRESENT/DISABLED
>                                              
> Re-key needed                                False
.......
> TLS                                          Disabled

Seems your ME is running fine and doing as it’s supposed to do by it’s configuration

Follow this guide (section D4)

But in addition between end of step 6 and step 8 (step 7 not relevant for your setup) change these settings in addition:

Then continue to follow the guide with step 8.

This should enable vpro/AMT if all the other conditions are fullfilled.

Update:
Followed the instructions as @lfb6 proposed, enabled AMT items it the FITC config.

First I tried reusing my hanging SPI dump as base, but it again stopped after DELL logo.

Next, I used the ‘BIOS Region’ from @Pk4Tech, and the laptop booted correctly, including AMT/vPro menu’s.

I compared my ‘BIOS Region’ with the one provided by @Pk4Tech, and noted that NVRAM items were cleaned.
UPDATE: I found that Pk4Tech used latest Precision7520 BIOS 1.24.0 (20May2022), and used section_0_1.24.0.payload as ‘BIOS Region’

https://www.dell.com/support/home/nl-be/drivers/driversdetails?driverid=c5k3r

Precision_7x20_1.24.0.exe_decompressed.hdr.extracted/section_0_1.24.0.payload - copied to ‘BIOS Region’ under FITC

Most important, the laptop works now, thanks @lfb6 and @Pk4Tech :+1:

1 Like

Good to hear it worked. :+1:

If you had extracted the Dell bios update with Dell_PFS_Extract you’d have got a folder with a plain stock bios region which normally has an empty NVRAM. So in your case changing the bios region to this stock region was all that was needed to get a empty NVRAM. In your 50+ MB zip it’d be section_0_1.23.1.payload, can’t find it in the hdr, and BIOS_IMG.rcv you’d hav eto unzip, and then extract the file ‘2’ again with Dell_PFS_Extract…

But NVRAM might be the place where some of the board specific data are stored- (some?) Intel NUCs do have their serials, service tags in NVRAM.Other vendors have/had data areas in padding, Dell starts with DVAR, Lenovo had LENV. Otherwise many Intel boards store their MAC address in GbE region, simply flashing a complete stock firmware would erase that. So first rule is: Always dump a valid backup (just as you did) so that you possibly can restore machine specific data.

3 Likes

I have No word, Thanks