[Request] DELL T7920 Embedded controller recovey.

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hkdio

New Member
Feb 21, 2024
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Build’s Name:
Operating System/ Storage Platform:
CPU: Silver XEON Silver 4116
Motherboard: T7920 (E93839 MT7314 TWC6K)
Chassis: T7920
RAM: DDR4 ECC 2999 16GB x 8
Add-in Cards: NVIDIA Quadro P40
Power Supply: T7920 1400W power supply



This is my first post in this forum,

Yesterday, I got my 4th DELL workstation (T5500, T5600, T7600), the latest machine is a secondhand T7920



After benchmark program burn test for 24 hrs, I decide to upgrade bios from 2.6.3 (yr 2020) to latest version.
First upgrade trial is a direct upgrade to 2.35.0. Upgrade file not execcute after reboot.
Second trial is upgrade to 2.16.0. (7X20T_2.16.0.exe). Bios updated executed after workstation rebooted..

However, the upgrade process stalls at 33% of phase 3 : EC (Embedded controller) flashing, fan run at full speed and no progress update for an hour.
Finally I decide to push power button and power cycle.
After power cycle, workstation fan run at full speed and power is always on, no display, and no bios warning when I remove ALL DIMM memory.

Inside T7920, there have 2 eeprom
Motherboard model: E93839 MT7314 TWC6K
EEPROM #1 : MX25L25673GMI-08G , 3 Volt , 32MByte SOP-16
EEPROM #2 : MX25V4035F-M2I, 2.5V Volt , 4Mbit, SOP-8


From DELL Precision_7920_Tower_Technical_Guidebook.pdf > "Statement of Volatility"
32MByte is bios,
4Mbit is Embedded controller

Capture.PNG
My new workstation got bricked, Embedded controller code corrupted.
This is my first time got Embedde controller data corrupted,

When I ask for local computer repair service, they replied me they have no this bios on hand and not able to recover

I have a TL866II+ programmer for game console bios clone, TL866II can recognize MX25V4035F-M2I eeprom
Maybe it can help me to recovery EC data.

But when I extract DELL update exe file. "7X20T_2.6.3.exe (using Dell_PFS_Extract.py), I got confused.

Code:
(Size / Filename:)
  16,777,216 - "7X20T_2.6.3 -- 1 System BIOS with BIOS Guard v2.6.3.bin"
     294,889 - "7X20T_2.6.3 -- 2 CPLD vA.8.bin"
      73,664 - "7X20T_2.6.3 -- 3 7920T Embedded Controller v1.1.23.bin"
      68,544 - "7X20T_2.6.3 -- 4 7820T Embedded Controller v1.1.21.bin"
       8,192 - "7X20T_2.6.3 -- 5 Gigabit Ethernet v0.2.bin"
   7,348,224 - "7X20T_2.6.3 -- 6 Intel Management Engine v11.22.70.1622.bin"
       2,168 - "7X20T_2.6.3 -- 7 System Map v1.0.1.bin"
       2,432 - "7X20T_2.6.3 -- 8 PCR0 XML v0.0.0.1.xml
         107 - "7X20T_2.6.3 -- 9 Model Information v1.0.0.0.txt
               9 File(s)     24,575,436 bytes
The size of .bin file didn't match the eeprom size, and a lot of bin file instead of single bin in old bios.
I have no idea how to compile bin file for Embedded controller

Can anyone tell me how to compile embedded controller .bin file for recovery,
or share me T7920 both 32MB + 4Mbit .bin file for recovery

Million thanks,
 
Last edited:

AGreenMan

New Member
Apr 2, 2024
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Hello hkdio,

I ran into the same problem and have been working on it for two days. So thank you for posting here. Did you find a resolution as I am on the exact same track of understanding.

From above, you the file "7X20T_2.6.3 -- 3 7920T Embedded Controller v1.1.23.bin" installed to the EEPROM #2 : MX25V4035F-M2I, 2.5V Volt , 4Mbit, SOP-8, if your update failed where you say it did, is what you want. I do not know where my update failed as I was not present for the power outage where the UPS system ran out of energy as well!

I wouldn't be surprised if my machine stalled where your experienced the stall as well, so I'm willing to work with you on this together.

-Greenman
 
Last edited:

hkdio

New Member
Feb 21, 2024
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Hello AGreenMan

Please identify the issue before action:

1. If fan run at full speed + power button no respond and keep power on, even unplug all CPU / RAM, fan still run at full speed, it is EC issue.
2. But, if you unplug RAM has post code (beep sound , power led flashing), or system can auto shutdown after few minutes, it is BIOS issue, you need a good BIOS bin file to recover the system.


I fixed my computer, using a quite expensive way:
1. Buy another T7920 motherboard (Second hand, around 3K usd)
2. De-solder MX25V4035F-M2I, 2.5V Volt from good motherboard (SOP8 Clamp will trigger EEPROM writer over-current)
3. Clone "GOOD" Embedded controller rom image
4. De-solder bad MX25V4035F-M2I, write good code to it
5. Solder to motherboard.

Attach is working EC EEPROM file.
 

Attachments

Last edited:

AGreenMan

New Member
Apr 2, 2024
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Hello hkdio,

That is perfect perfect information for me to diagnose it, and I'll use it as I progress through the steps you've provided.
I have the BIOS & EC files extracted from the most recent version from Dell. Thank you so much for being available to work on this.
 

AGreenMan

New Member
Apr 2, 2024
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Finally got some time, and the right tools, to look into this. On my EEPROM about the first 1/3rd data block equivalent to what you supplied is erased (e.g. my EEPROM is 0xFF through 0x7000 out of 0x131CF length in your file) including the first 0x0000 through 0x1000 which the Dell binary doesn't contain. The binary from the Dell update package is missing a great deal of sectors and that is why it isn't easily programmable with a straight write of the BIN file. I'm currently using the file you provided to hack together a file that "looks" right for the later 2022 through 2024 BIOS patches. Dell hasn't updated the actual EC controller BIN file since 2022 according to the copywrite.