Hacking Compressed VC games are uncompressed before load?

[sr_corsario]

Hello!!

I have just see a compressed file in a NeoGeo VC game. (KOF95 - USA) In this case is the game file, (game.bin.z) for this reason is importan (for me xD)

"The problem" with neogeo roms is the size because the game is charged into the ram and it needs to fit in it.

Now, appear a game.bin.z file with just the half size of it should have!! (15Mb instead of 30Mb aprox)

Certenlly we will need to know how to compress it in order to inject a new game...

However... my question is:

When a VC game is started, its charged on ram, ¿Is the main.dol (1.app) loading the game compressed (romc for exemple) or it decompress it before playing?

For one hand i think it decompress the rom (game file) on ram (is it called on the fly?) to load it later easylly but for the other hand... its a waste of time... and for ex. on KOF95 it dont spend many time for instance i supouse it load the game.bin.z as is.

Im asking all of this because could be a nice door for a new pack of neogeo injections... I mean big games...

Any idea?
And what about .z file? I tried with 7z, winrar, winzip but didnt work...

Sr Corsario


Edit:I was able to inject compressed games using stev418 information, and the small ones works... but unfortunately it looks like to decompress the game.bin.z into memory for instance...

big games will not work

 

[s3phir0th115]

They use a compression method that 7z, WinRAR, etc don't understand.

I think I used something called U8 to deal with the compressino of some of the stuff.

As for what roms use, I wish I could tell you. I have yet to be able to decompress some VC stuff, unless they've updated the compression/decompression tools. (Super Mario RPG for instance.)

 

[sr_corsario]

I think I used something called U8 to deal with the compressino of some of the stuff.

As for what roms use, I wish I could tell you. I have yet to be able to decompress some VC stuff, unless they've updated the compression/decompression tools. (Super Mario RPG for instance.)

Mmm .... no, I know more ot lease U8 and romc compresion and unfortunally its not the case.

Edit: And the most important is to know if the game.bin.z is decompressed or not. (or any other compressed rom file)

 

[FIX94]

game.bin.z? It could be U8, that's fast and good compressed. It also could be lzh8 or this romc compression for newer games.

 

[sr_corsario]

game.bin.z? It could be U8, that's fast and good compressed. It also could be lzh8 or this romc compression for newer games.

It Dont have any U8 header

 

[s3phir0th115]

Well, I remember using u8 tool or something like that at least once when I was injecting Master Quest into the normal Ocarina of Time. I don't know which files used it, but I know at least one did.

 

[FIX94]

game.bin.z? It could be U8, that's fast and good compressed. It also could be lzh8 or this romc compression for newer games.

It Dont have any U8 header

It could also be LZ77. You could try to decompress the file with LZ77Mii (part of Wii.cs Tools)

 

[sr_corsario]

I tried with:

gbalzss.exe
u8extr.exe
romc.exe i get a file to big ... 55Mb... it should be near to 30Mb

It could also be LZ77. You could try to decompress the file with LZ77Mii (part of Wii.cs Tools)

Thanks but it dont work ... it give that mesage "File is not LZ77 compressed"

 

[FIX94]

I tried with:

gbalzss.exe
u8extr.exe
romc.exe i get a file to big ... 55Mb... it should be near to 30Mb

It could also be LZ77. You could try to decompress the file with LZ77Mii (part of Wii.cs Tools)

Thanks but it dont work ... it give that mesage "File is not LZ77 compressed"

You could also try lzh8:
http://hcs64.com/files/lzh8_cmpdec08.zip

 

[sr_corsario]

You could also try lzh8:
http://hcs64.com/files/lzh8_cmpdec08.zip

No working "Not LZH8"

Thanks for your help anyway!!

 

[stev418]

ok did some digging in the 01.app with hex editor and found something of interest

inflate 1.2.3 Copyright 1995-2005 Mark Adler

so im thinking compression is DEFLATE which iirc is zlib? :S so its zlib of some sorts anyway

 

[sr_corsario]

On elotrolado the user GameZelda suggest as well zlib compression and a tool.
Its offzip (Luigi Auriemma) website and with the option:

"offzip -a game.z game 0x0" i got a 00000000.dat file with 52.822.080 bytes it looks like to be a correct (more or less) file... moreover I can see a diferent used bios on the archive...

 

[WiiPower]

On elotrolado the user GameZelda suggest as well zlib compression and a tool.
Its offzip (Luigi Auriemma) website and with the option:

"offzip -a game.z game 0x0" i got a 00000000.dat file with 52.822.080 bytes it looks like to be a correct (more or less) file... moreover I can see a diferent used bios on the archive...

Then i hope you have both games in the "original" form, so you can determine how the currently used game.z file was build. I assume that the used bios is essential for this to work.

 

[sr_corsario]

I assume that the used bios is essential for this to work.

Well... bios on neogeo vc games dont matter a lot... can be used uni-bios ... and the "old" vc neogeo games have a diferent one.
However... in hex edit, the 0.dat file looks like to be good.

Im very excited!!

Edit:File order is changed XD (talking about P,M,V,S,C, and bios order on game.bin)

 

[WiiPower]

I assume you have both games in "original" form? I think i would try to make some sort of diff of both files and then apply it to your uncompressed .z file.

 

[sr_corsario]

Now "both" are not igual than before... because data order insite game.bin is diferent... this afternoon i will try to finish "the study"

Thanks for your interest

Edit:Now the file order looks like to be:

header
S file
C files (with "usual" modification and extra FF's)
V (with extra FF's)
Bios
P file (with swap, as usual)
M file

 

[stev418]

hey man, i used a tool called xpert2 and its included zlib tool, was able to decompress rom and then compress back to a 100% match, i dont have the original rom to check but looks like it will do the trick. I sent you pm with link to xpert

 

[sr_corsario]

Thanks stev418

The compression/decompression is working perfectlly

Now i hope it works on big injections

Will try first with the usual "small" games and later with the big ones


Thanks again!!

Sr Corsario


Sr Corsario


Edit:I was able to inject compressed games using stev418 information, and the small ones works... but unfortunately it looks like to decompress the game.bin.z into memory for instance... big games will not work

 

[Deleted member 180466]

Thanks stev418

The compression/decompression is working perfectlly

Now i hope it works on big injections

Will try first with the usual "small" games and later with the big ones


Thanks again!!

Sr Corsario


Sr Corsario


Edit:I was able to inject compressed games using stev418 information, and the small ones works... but unfortunately it looks like to decompress the game.bin.z into memory for instance... big games will not work

http://gbatemp.net/index.php?showtopic=851...p;#entry1126169

 

[sr_corsario]

GHBAinem thanks for reaply, but is not the same compression.

however now this thread is finish (at less for me) because the answer to the "question" is unfortunately YES

When the "ram" is full, the wii get freeze...

Will not be possible big injections.