Debricked! Asus DualBios. Why are chip contents so different? Should be the same?

greenspark

n00b
Joined
Sep 2, 2016
Messages
2
I have a Asus P8B75-M-LX that I purchased as a working board, but it didn't.

Trying to figure out what's wrong with it. Tested supported processors from first bios version, several RAMs but it does not work.

Sympthoms: when plugged in, I get onboard green led lit. When I short Power-On jumper pins, the mobo starts fans, but nothing is displayed on the screen, even with an additional onboard VGA. No beeps. No boot. All signs of life beyond this is are only seen when I remove RAMS, that I can get it to make beeeeep-bip-bip.​

OK Trying to figure out if it could be a BIOS problem, I created a backup from both onboard BIOS chips and get them identified by FD44Editor.


  • Left CHIP: Winbond 25Q64FVA1G is detected by CH341A programmer as a W25X64 chip (8MByte). Contents can be read. Chip dump can be read with FD44Editor and is detected as P8B75-M-LX, BIOS date: 10/10/2012, BIOS version: 0803, ME version: Not present, GbE version: Not present (and some additional UUIDs, serials and so).
  • Right CHIP: Winbond 25Q64FVA1G is detected by CH341A programmer as a W25X64 chip (8MByte). Contents can be read. Chip dump can be read with FD44Editor but I get: "Error parsing BIOS DATA. $BOOTEFI$ signature not found. Please open correct ASUS BIOS file". The file is totally different from Left chip's version and does not look like a BIOS file.


Humm... I expected to see an ASUS bios on both chips.

So I assumed the right chip to be corrupt and copied the left chip to the right chip. (I made a backup before).

- Both chips with left chip info: No boot. It does not even beep when RAMs are removed.

So I prepared for a total debricking using Tools to flash and recover BIOS on ASUS P8xxx boards (FD44Editor, FTK).

  • I downloaded BIOS version 1403 from ASUS and used FD44Editor to prepare a new BIOS based on the info read in the left chip. Downloaded a CAP file. FD44Editor gave me the .bin file.
  • Flashed left and right chips.
  • Again, No boot. It does not even beep when RAMs are removed.

Okay, I may have some problem with the new BIOS version. I downloaded the same version in the chips: 0803

  • I downloaded BIOS version 0803 from ASUS and used FD44Editor to prepare a new BIOS based on the info read in the left chip. Downloaded a CAP file. FD44Editor gave me the .bin file.
  • Flashed left and right chips.
  • Again, No boot. It does not even beep when RAMs are removed.

So far so good, I preferred to go back:
  • Recovered Left backup to Left chip
  • Recovered Right backup to Right chip.
  • No boot, but at least beeps when RAM is removed.
Swapping left and right chips leads again to a board that does not boot and does no beeps.

Looks like there's something in these chips that needs to be here and there. Hummm.... Any clues?
 

greenspark

n00b
Joined
Sep 2, 2016
Messages
2
Just made another test and I got to debrick it:

- I just programmed left chip, with the BIOS 1403 BIN file that FD44editor gave me, after reading the info from my left chip BIOS (v0803), and applying that info to the manufacturer v1403 BIOS CAP file. Right chip remained with original contents, that are *not* a Asus BIOS file.


Note: the image shows v0803 for left chip: I programmed 1403 to left chip. The right chip (does not contain a valid BIOS file) remained as it was.

BINGO, the mobo started with bios 1403 and was soon up and running after loading BIOS defaults.

So, I got the mobo repaired, but I earned some knowledge that I wanted to share:

BOTH CHIPS IN ASUS CRASHFREE3 DO *NOT* CONTAIN A COPY OF THE BIOS. Only LEFT ONE in P8B75-M LX

I don't know whats stored in RIGHT CHIP. I have the dump, but does not look like a BIOS dump.




Report: Marc Malagelada Personal Portfolio: De-Bricking an ASUS P8B75-M LX
 

Azrak

Gawd
Joined
Oct 4, 2015
Messages
890
The manual does not say that the Asus P8B75-M-LX is a dual-BIOS motherboard, so I'll guess that only the left chip actually contains the BIOS and the right chip contains a special low level BIOS that is encrypted or contains parameters/timing info that the left chip BIOS needs to operate and/or may contain the Intel SBA (Small Business Advantage) support code that the motherboard has as one of its touted features.
 

skizzo76

n00b
Joined
Nov 5, 2017
Messages
1
Hi friends,
I'm looking DUMP file of right chip of P8B75-M LE. Someone can help me?

Thanks in advance
 

RonWolfs

n00b
Joined
Aug 17, 2018
Messages
1
Hello Folks,


need some help.

I am looking for the both Dumpfiles (L+R) of a P8B75-m LX Board withe Winbond 25Q64FV chips.

Does someone have a downloadlink for me. (I can support a uploadlink if needed)


That would be wonderfull.


Thankx a lot.


Ron
 
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