Convert BF and BMD into flowscripts and messagescripts

As previously mentioned, AtlusScriptCompiler can compile .FLOW and .MSG into .BF and .BMD respectively. Read the previous sections for more information.

1. Specifying the Input File

First, you must tell the program what file we're working with. For compiling, this must be a .FLOW or .MSG file.

C:\Users\Username>"C:\Path\To\AtlusScriptCompiler.exe" "C:\Path\To\"

You can simply drag AtlusScriptCompiler.exe and then onto the command prompt window. This will automatically wrap each paths in quotes, which keeps arguments separate in case your paths contain spaces.

2. Specify that you are Compiling

Now, let's tell the program what to do with that file. Add -Compile, separated by a space.

C:\Users\Username>"C:\Path\To\AtlusScriptCompiler.exe" "C:\Path\To\" -Compile

2. Specifying the Library

A Flowscript Library instructs the compiler on function names and parameters. In order to work with the input file, you have to tell the compiler which Library to use with -Library.

C:\Users\Username>"C:\Path\To\AtlusScriptCompiler.exe" "C:\Path\To\" -Compile -Library P5

Included Libraries

Library Name






















Not all games have libraries available. Knowledge of reverse engineering game executables is required to generate a library, as you'll have to find the offsets of function signatures yourself. A sample script for P3/P4 (PS2) can be seen here.

3. Specifying Output Format

You should also choose an Output Type with -OutFormat. This determine the version and endianness of the generated BF or BMD.

C:\Users\Username>"C:\Path\To\AtlusScriptCompiler.exe" "C:\Path\To\" -Compile -Library P5 -OutFormat V3BE

Output Types

Output Type


Persona 5 BF


Persona 5 (PS3) BMD


Persona 5 (PS4) & Persona 3/4 (PS2) BF/BMD


4. Specifying Encoding

An Encoding can be specified using -Encoding. It lets the compiler know what set of characters to use.

C:\Users\Username>"C:\Path\To\AtlusScriptCompiler.exe" "C:\Path\To\" -Compile -Library P5 -OutFormat V3BE -Encoding P5


Game Name


Persona 5


Persona 4


Persona 3 (FES)


PersonaQ(2) or any game using Shift-JIS/CP932


5. Specifying the Output File

Finally, you can name the Output File using -Out.

C:\Users\Username>"C:\Path\To\AtlusScriptCompiler.exe" "C:\Path\To\" -Compile -Library P5 -OutFormat V3BE -Encoding P5 -Out "C:\Path\To\"

If -Out is not specified, it will default to the input filename and folder, but with the output filetype appended. In this case, that would be C:\Path\To\

At this point, you can press Enterto begin compiling. But, there are a few optional commands which might be useful to you.

6. Hooking

Hooking can be handy when you're compiling a .FLOW and only want to replace specific procedures in an imported .BF.

AtlusScriptCompiler is not perfect, so it doesn't hurt to be proactive. With hooks, we can avoid potential compiler issues when recompiling an entire .BF script.

Enable Hooking by adding the-Hook argument.

When compiling your .FLOW into .BF, this redirects existing procedures in an imported .BF file to replacement procedures with a matching names that end in _hook_().

The original procedure still exists and can be called by name in your .FLOW script, since the original data is not overwritten when hooking a function. References to the original procedure in the original .BF are simply redirected to your replacement.

C:\Users\Username>"C:\Path\To\AtlusScriptCompiler.exe" "C:\Path\To\" -Compile -Library P5 -OutFormat V3BE -Encoding P5 -Out "C:\Path\To\" -Hook


  1. Decompile the .BF that you're referencing in the .FLOW you're compiling.

  2. Open the .FLOW and copy the procedure you want to edit.

  3. Paste it into your .FLOW that references the .BF, and add _hook to the procedure name.

  4. Edit the procedure however you'd like.

  5. Import the original .BF file.

  6. Compile your new .FLOWwith the-Hook argument.


Now that you know how to (de)compile with AtlusScriptCompiler, you're ready to read, edit, and create scripts. If you haven't already, read on to see how to use the GUI to make (de)compiling even easier:

Run via GUI

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