RMHook/README.md

RMHook

A dynamic library injection tool for the reMarkable Desktop macOS application, enabling connection to self-hosted rmfakecloud servers.

Overview

RMHook hooks into the reMarkable Desktop app's network layer to redirect API calls from reMarkable's official cloud services to your own rmfakecloud server. This allows you to maintain full control over your documents and data.

Features

• Network request interception and redirection
• WebSocket connection patching

Installation and usage

Important legal notice

⚠️ For legal reasons, this repository does not include a pre-patched reMarkable app. However, the latest compiled dylib is available in the Releases section.

Step 1: Prepare the reMarkable app

Uses the reMarkable Desktop app from your Applications folder or download it fresh from the Mac App Store.

Step 2: Inject the dylib

Use the provided injection script:

./scripts/inject.sh reMarkable.dylib reMarkable.app

This script will:

• Copy the dylib to the app bundle's Resources folder
• Inject the load command into the executable using optool
• Remove the code signature and resign with ad-hoc signature
• Remove the _MASReceipt folder
• Fix file ownership

Step 3: Handle document storage

Important path changes

The original Mac App Store version stores data in sandboxed locations: Original sandboxed paths:

• App data: ~/Library/Containers/com.remarkable.desktop/Data
• Documents: ~/Library/Containers/com.remarkable.desktop/Data/Library/Application Support/remarkable

After re-signing, the app is no longer sandboxed and will use standard paths:

• Config: ~/Library/Preferences/rmfakecloud.config
• Documents: ~/Library/Application Support/remarkable

Migration options

Option 1: Create a symbolic link (recommended)

ln -s ~/Library/Containers/com.remarkable.desktop/Data/Library/Application\ Support/remarkable \
      ~/Library/Application\ Support/remarkable

The symbolic link approach allows you to keep using the original App Store version alongside the patched version.

Option 2: Move files

mv ~/Library/Containers/com.remarkable.desktop/Data/Library/Application\ Support/remarkable \
   ~/Library/Application\ Support/remarkable

Step 4: Configure rmfakecloud server

Quickly access the configuration file from the app's Help menu: Edit the configuration file at:

~/Library/Preferences/rmfakecloud.config

Example configuration:

{
  "host": "your-server.example.com",
  "port": 443
}

Step 5: Launch the patched app :p

How it works

RMHook uses tinyhook to hook into Qt framework functions at runtime:

1. QNetworkAccessManager::createRequest - Intercepts HTTP/HTTPS requests
2. QWebSocket::open - Patches WebSocket connections

When the app attempts to connect to reMarkable's servers (e.g., internal.cloud.remarkable.com), the hooks redirect these requests to your configured host and port.

Configuration

The config file (~/Library/Preferences/rmfakecloud.config) supports the following keys:

Key	Type	Default	Description
host	String	example.com	Your rmfakecloud server host
port	Number	443	Your rmfakecloud server port

If the config file doesn't exist, it will be created automatically with default values on first launch.

Troubleshooting

App won't launch

• Ensure the code signature was properly applied
• Check that xattr -cr was run to clear quarantine attributes
• Verify the dylib is in Contents/Resources/ folder

Document sync issues

• Ensure your rmfakecloud server is running and accessible
• Verify the storage path migration was completed

Credits

• tinyhook: Antibioticss/tinyhook - Function hooking framework
• rmfakecloud: ddvk/rmfakecloud - Self-hosted reMarkable cloud
• optool: alexzielenski/optool - Mach-O binary modification tool

License

This project is licensed under the MIT License. See the LICENSE file for details.

Disclaimer

This project is not affiliated with, endorsed by, or sponsored by reMarkable AS. Use at your own risk. This tool modifies the reMarkable Desktop application and may violate the application's terms of service.

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.

Building

1. Clone the repository:

git clone http://github.com/NohamR/RMHook
cd RMHook

2. Compile the dylib:

./scripts/build.sh