How to identify a BIOS file

I downloaded the following BIOS update for the MSI 890GXM-G65 
(http://www.msi.com/index.php?func=prodmbspec&maincat_no=1&cat2_no=&a...
cat3_no=&prod_no=2012).

http://download1.msi.com/files/downloads/bos_exe/7642v12.zip

The zip file contains the following files:

4.0K 7642v12/7642v1x.txt
2.1M 7642v12/A7642AMS.120
148K 7642v12/AFUD4310.EXE
 56K 7642v12/How to flash the BIOS.DOC

Am I right to assume that the largest file "A7642AMS.120" (2.1 MB) 
is the BIOS file? Here's the edited result of the "file" command on 
the files within the directory:

7642v12/7642v1x.txt:               ISO-8859 English text [...]
7642v12/A7642AMS.120:              data
7642v12/AFUD4310.EXE:              MS-DOS executable
7642v12/How to flash the BIOS.DOC: CDF V2 Document, [...]

The file "A7642AMS.120" is identified only as generic "data".

[Peter Lemenkov]

Hello!

2010/4/22  :
> I downloaded the following BIOS update for the MSI 890GXM-G65
> (http://www.msi.com/index.php?func=prodmbspec&maincat_no=1&cat2_no=&a...
> cat3_no=&prod_no=2012).
>
> http://download1.msi.com/files/downloads/bos_exe/7642v12.zip
>
> The zip file contains the following files:
>
> 4.0K 7642v12/7642v1x.txt
> 2.1M 7642v12/A7642AMS.120
> 148K 7642v12/AFUD4310.EXE
>  56K 7642v12/How to flash the BIOS.DOC
>
> Am I right to assume that the largest file "A7642AMS.120" (2.1 MB)
> is the BIOS file?

You can use bios_extract utility for that (however this particular
BIOS image causes bios_extract to segfault):

Workplace ~/work: unzip 7642v12.zip
Archive:  7642v12.zip
  creating: 7642v12/
 inflating: 7642v12/7642v1x.txt
 inflating: 7642v12/A7642AMS.120
 inflating: 7642v12/AFUD4310.EXE
 inflating: 7642v12/How to flash the BIOS.DOC
Workplace ~/work: cd 7642v12/
Workplace ~/work/7642v12: ../bios_extract/bios_extract A7642AMS.120
Using file "A7642AMS.120" (2048kB)
AMI95 Version   : 0800 (03/31/10)
0x1F0000 ( 65536 bytes) -> amiboot.rom
Ошибка сегментирования
Workplace ~/work/7642v12:

[Michael Karcher]

Am Donnerstag, den 22.04.2010, 05:51 +0000 schrieb [e-mail]:
> 4.0K 7642v12/7642v1x.txt

Explanation of the update
> 2.1M 7642v12/A7642AMS.120

BIOS image file. If you take "M" as 1024*1024 bytes, it's exactly 2 MB.
Power-of-two sizes are also typical BIOS images.
> 148K 7642v12/AFUD4310.EXE

Updater program for DOS "Award Firmware Update for Dos"
> 56K 7642v12/How to flash the BIOS.DOC

Instructions for updating.
> Am I right to assume that the largest file "A7642AMS.120" (2.1 MB) 
> is the BIOS file?

Yes.
> Here's the edited result of the "file" command on 
> the files within the directory:
>
> 7642v12/7642v1x.txt:               ISO-8859 English text [...]
> 7642v12/A7642AMS.120:              data
> 7642v12/AFUD4310.EXE:              MS-DOS executable
> 7642v12/How to flash the BIOS.DOC: CDF V2 Document, [...]
>
> The file "A7642AMS.120" is identified only as generic "data".
>
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