Disclaimer

GP2Mem edits the memory of a running process. It can cause crashes, corrupted game state, or unexpected behavior. Use at your own risk.

GP2Mem

GP2Mem is a memory editing tool for the classic racing game Geoff Crammond’s Grand Prix 2. It’s compatible with both DOSBox-based setups and the x86GP2 mod.

This tool wouldn’t be possible without Hatcher’s help on Discord, rremedio’s comments on the GP2 forum, and most notably Rene Smith’s IDA disassembly of the game.

Features

• Live viewing of per-car game state (positions, speed, flags, fuel, etc.)
• Editing selected fields for one car or all cars
• Built-in helpers for enums/bitflags and readable “pretty” displays
• Custom scripts (notably Safety Car and Slipstream)
• Full struct view to explore additional/unidentified fields

Installation

Option 1: Download a release (recommended)

1. Go to Releases on GitHub.
2. Download the latest .zip.
3. Extract it and run GP2Mem.

Note: The packaged build is made with PyInstaller. Some antivirus products may show malware warnings because bad actors sometimes abuse PyInstaller, and because this tool reads/writes process memory. If you don’t trust the binary, use the “Run from source” method below.

Option 2: Run from source (venv)

Note: Use Python 3.10 or above

1. Clone the repo:

git clone https://github.com/ilya-ssh/GP2Mem.git
cd GP2Mem

2. Create and activate a virtual environment:

python -m venv .venv

Windows:

.venv\Scripts\activate

3. Install dependencies:

python -m pip install -U pip
python -m pip install -r requirements.txt

4. Run:

python src/main.py

How to start

1. Start Grand Prix 2 via DOSBox or the x86GP2 mod
2. Start GP2Mem
3. Ensure the game executable name matches the process name shown in GP2Mem (default is x86GP2_inline.exe)
4. Launch a Quickrace (recommended: start with AI cars only)
5. While the AI cars are revving up at the start, press Find Base (Grid) at the top of GP2Mem.
   • GP2Mem will scan memory and find the required base address.
6. You can now exit Quickrace and start your actual race/practice/quali session.

When you restart the game, you may need to repeat the Find Base (Grid) process again. This design is intentional to maintain compatibility with older GP2 builds used in DOSBox and older x86 versions.

Editing values

GP2Mem is organized into tabs for different groups of fields (race state, timing, controls, pit/failure, tires/damage, flags, aero/weight, etc.). In general:

• Select a car in the Overview table.
• Use the Details tabs to view/edit fields.
• Many fields can be written to the selected car or to all cars.

Custom scripts

There are also custom scripts, most notably:

• Safety Car
• Slipstream

These can change gameplay behavior by applying repeated memory writes during runtime.

Warning about replays

Do not attempt to use the game’s replay feature while using GP2Mem—this can break the race state.

Exploring deeper (Full Struct)

If you want to dig further, open the Full Struct tab to browse and experiment with additional/unidentified values and flags.

Contributing / Feedback

Please feel free to:

• Open issues for bugs or feature requests
• Submit pull requests
• Fork the repo and modify the tool to suit your needs

Experimentation is encouraged just do it carefully and expect that some values/flags may have side effects.

Support

If you like this repo, please give it a star.

If you want to donate something (not encouraged but appreciated), you can do so here:

• Ethereum: 0xE85984123B0449e6EFDC7FcaF28FFa9731868799
• Bitcoin: bc1qgkkfx6ef69avp5d6fkx7v606j9g8vsdtz7cwaw