simforge: Run iOS Apps on Apple Silicon Simulators

simforge is a tool that enables running ARM64 iOS apps on Apple Silicon iOS simulators by modifying the Mach-O binary headers to indicate simulator compatibility.

Installation

Using Swift Package Manager

git clone https://github.com/etharbuckle/simforge.git
cd simforge
swift build -c release

This will create two executables:

• .build/release/simforge: The core tool
• .build/release/simforge-cli: An interactive CLI wrapper

Usage

Option 1: Interactive CLI (Recommended)

The CLI tool provides an interactive interface that guides you through the process:

1. Place your .app or .ipa file in the apps directory
2. Run the CLI tool:

.build/release/simforge-cli

3. Follow the interactive prompts to:
   • Select the app to process
   • Choose a signing identity
   • Select a simulator

The CLI will automatically:

• Extract IPA files if needed
• Convert the app for simulator use
• Sign all frameworks and the main bundle
• Launch the simulator if needed
• Install and launch the app

Option 2: Manual Usage

If you prefer manual control, you can use the core tool directly:

1. Extract the .app bundle from the IPA:

unzip /path/to/your-app-decrypted.ipa -d /path/to/destination/

2. Convert for simulator:

simforge /path/to/Payload/YourApp.app

3. Code sign the modified app:

# Sign frameworks first
codesign -f -s "$SIGNING_ID" /path/to/Payload/YourApp.app/Frameworks/*

# Then sign the main app bundle
codesign -f -s "$SIGNING_ID" /path/to/Payload/YourApp.app

4. Install to simulator:

xcrun simctl install "SIMULATOR_UUID" /path/to/Payload/YourApp.app

Configuration

The CLI tool creates a .simforge_config file that can store your simulator preference. To change the simulator, simply delete this file and run the CLI tool again.