How to split apart an uncompressed .pac file?

[Game_Master001]

I know there are no tools for regular compressed .pac files from NDS games, but what I'm having here are uncompressed .pac files (from the Yu-Gi-Oh games World Championship 2007 and 2008). It's literally just files grouped together without any compression whatsoever: the files within and the contents of those files within can be seen just by opening it with a hex editor. I was wondering if this makes any difference, if there are any tools or tricks to extract the files from these kind of .pac files?

 

[FAST6191]

.pac is a fairly generic extension and I know of at least 6 different variations on the DS. Can't remember if I did something with any of the yugioh games here though (most times people just want deck cheats and to change the limited deck customistion against AI not knowing that breaks AI in a hurry)

In most cases then usually at the start of the fie will be some kind of indicator as to how large each each sub file within is or its location (in which case next address-current address = file size), other times said info might be in a separate file in the same directory.

I did a similar thing the other day in
https://gbatemp.net/threads/need-help-ripping-files-from-call-of-duty-black-ops-ds.633221/

The main tool I used is https://web.archive.org/web/20170218180937/http://min.midco.net/cracker/filecutter.zip if you just need a quick thing to say slice up this much of the file starting at this address (tweak your hex editor to dump the addresses in a nice list, stuff that in a spreadsheet, easy enough to built up the command to get a little batch file going on, hard to then rebuild the thing after editing but there are still ways and if you only want to poke around then hey).

 

[mn1712trungson]

If you can find the offset table (list pointer to the file) and size,
you can write the simple QuickBMS script and parse the whole package.

The sample PAC header:

Or use the spreadsheet and make the batch with the filecutter, like FAST said:

With QuickBMS, you can write the extract script and reimport the modified file with the same script.
In a basic way, you can cut the PAC header and the data chunk. Use batch and parse the whole data chunk.
After editing files, use the simple tool copy on Windows (https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/copy) or cat on Linux

to combine the whole binary package with:​

COPY /V /B *.dat \combine\dat_chunk.pac​

combine edited header with:​

COPY /V /B dat_chunk.pac+header.pac \combine\dat.pac​