Unable to decode FS25 files

[TAEMBO]

This script works fine to decode Farming Simulator 22 files, however Farming Simulator 25 seems to be using a different format - an error 'File "{filePath}" contains an invalid .l64 header.' is returned for any and all l64 files retrieved from FS25.

Here's a download link to one of the .l64 files in question: https://cdn.taembo.net/main.l64

[tn4799]

An importent information is that the l64 files differ from each other starting at the third byte, compared to the old files where the first 16 bytes always are the same.

[tn4799]

@VidhosticeSDK Would your algorithm also work if the bytes now change from row to row? Since in fs22 the files all had the same first 16 bytes.

[19BlueDragon83]

If someone has a solution, it would be nice if he would share it :). How did you open the .gar file?

[scfmod]

FS25 does not use LuaJIT anymore, they now use Luau. The first 2 bytes of the .l64 is the version (0x02 0xEF = luau bytecode version 3 when interpreted by the game .exe). So the old lookup tables won't work at all for these :-) Other than that I don't have much information on it.

[scfmod]

0x02, 0x13, 0x0a, 0x08, 0x01, 0x07, 0x02, 0x02

[Rockstar94FS]

Hi, I found a way to decode the .l64 files. https://github.com/Rockstar94FS/Farming-Simulator-L64-Decoder

Unfortunately, they are still unreadable. Does anyone know of any tool to decompile them?

[TAEMBO]

@Rockstar94FS What does this attempt decode them to? LuaJIT or Luau?

[Rockstar94FS]

@TAEMBO Luau bytecode

[scfmod]

That script will only decode FS19/FS22 .l64 files, not FS25

[Rockstar94FS]

It works with FS25, the algorithm is similar but different from that of FS19/FS22.

[CoderKane]

Rockstar's tool works for unlocking the l64 files! I wonder if some of the decompilers for Roblox lua scripts work since it also used Luau? Oracle decompiler supposedly works with LUAJIT 2.0-2.1 and Luau (bytecode version 3-6). Though it's paid software. Anyone gave it a try yet?

[scfmod]

Yeah my bad, it actually worked :-) I didn't notice the change of the formula, just that it used the same lookup table from previous versions. The lookup table I posted here works with the old formula

[TAEMBO]

@CoderKane https://github.com/xgladius/luauDec seems to be the most prevalent Luau decompiler out there based on my research that isn't pay-walled, however I'm unable to comprehend how to fully build it w/ make or with VS, have only gotten past the cmake part.

If anyone has any insight into that or knows a better solution, do let me know. I'm looking for something I can ship as a binary as opposed to a GUI or online web kind.

[scfmod]

luauDec only supports bytecode version 2 and unfortunately seems to fail randomly every time it's executed.

[19BlueDragon83]

Maybe this?

https://github.com/cadenmarinozzi/Luau-Decompiler

[scfmod]

It seems that the bytecode format in FS25 is a bit modified from the "standard" format. I can deserialize v4 bytecode generated by luau compiler without any problems, but not these files.

Edit: Seemingly the bytecode version they use is 3