GTA4 - EXE modification

[NTAuthority]

It seems Games for Windows Live adds a integrity check to the game EXE file -- when I modify even the tiniest byte in GTAIV.exe, I get the 'fatal error WS10', which seems to be caused by GFWL. Removing one of the GFWL files (.cat, .cfg or .cdf) also causes this error.

 

Has anybody already found a way to stop this integrity check from occuring, even if it is for other GFWL games?

[Dangta]

How about modifying memory in runtime? Might bypass the checks that way?

 

Also, has anyone gotten to any disassembling of the game yet? I'm trying to look for the address that all the vehicle spawning cheats use to create vehicles so that i can attempt to hook it in C/C++ and create a little spawning function so i can pass any carid i want onto it instead of their presets.

 

(Note. Lack of GTA:4 memory address thread)

[opium_addict]

Yes i am able to hook while in the process and bypass that check, however in the middle of gameplay there is a CRC check of some kind and xlive.dll crashes the process.

 

i have solved this by unhooking before that happens, but for hooks where you need to remain hooked for the duration of the game it is not desirable.

[Arlov]

Wouldn't it be possible to just disable GFWL somehow? or would that require decompiling and modification of the launcher/game-exe?

[opium_addict]

I have started an xlive.dll emulator project, but it seems if a "proxy" xlive.dll is in the GTAIV.exe directory, securom detects it and refuses to launch, i thought at first it was my "test" code for the xlive.dll emulator was flawed, which is probable, but my "xlive.dll" does not even get loaded.

 

You may be able to hook "LoadLibraryA" or "LoadLibraryW" depending on which is called to load the xlive.dll and return a false library.

 

That is what i was planning on next.