Need ROM file for Dell E6420 BIOS

its almost impossible .. best way is a working laptop to do a backup.

 

It's not impossible, it's just that apparently no one on this forum has actually worked to extract the ROM from the update applications. I've started this, and know the location where the compressed data is, but I need some more eyes on it to help figure out a) how to manually decompress or b) to help me figure out where the decompressed data is appearing in memory so it can be dumped one chunk at a time. Note that the signature I've found that locates compressed data seems to be relevant for E6410-E6430. So LatinMcG, since you're an experienced user, I would appreciate it if you could poke other experienced users and get them in touch with me so we can work on it. Thankyou

 

Hi,
there are some interesting strings in the "exe" file, for example: "inflate 1.2.3 Copyright 1995-2005 Mark Adler", the problem is that the compressed data has an offset, I tried to use many unzip utilities without success for this same reason. Also had been looking for a solution to extract the bios from a Dell bios update exe, that's for newer models, found a utility named "offzip.exe" which searches the complete exe file looking for compressed data and extracts it. For example, working with E6420A12.exe file I'm able to extract compressed data of 9,312,985 bytes, that's 8.88MBytes, the bios file for E6420 is only 8MB so if you have a dump of a corrupted bios it will be good to compare it against it and know where to cut. 16 bytes before the end of a bios there's usually a JMP or a NOP, in this case I believe is:

E9 97 2E 83 55 36 0B 8C 26 43 47 7A 12 37 7F 0A @ 823A87h

Decompressed file starts with: PFS.HDR


Now that the bios file is extracted and decompressed I can read some interesting strings off it, strings like the ones found in any other bios.

offzip.exe = Offset file unzipper 0.3.5

Command:
c:\offzip -a E6420A12.exe bios 0

where:
"-a" unzip all the possible zip data found in the file
"E6420A12.exe" is the executable bios update from which we want to extract the bios/compressed data
"bios" is the subdirectory where to extract the files
"0" is the file offset from where to start looking for compressed data


DRGN997

 

I got this working, I posted my code to

forums.mydigitallife.net/threads/44785-I-present-you-a-tool-to-decompress-Dell-UEFI-BIOS?p=750992

But you were on the right track, you basically need to know the right offset to the file and then zlib decompress. But I had already found the signature the updater used via RE. I wish I knew bout offzip before :-/

 

Oh, but the good thing about my script is you don't need to run it only on windows for linux folks like me

 

Ok. I decompressed E6420A19.exe and I received .dat file. I updated SILC to 2.2 but how to update bios this file or how to compress to EXE

 

Hi,

I got the same result. Now I got he BIOS hdr file but it starts with PFS.HDR. The dell firmware updater tool is expecting an RBU file.
The older BIOS files have an $RBUT header. So the question is how do you write this PFS file to the BIOS?

thanks