reMarkable Kaitai Specs

The reMarkable is a pretty cool e-ink tablet. The tablet stores a notebook's pen strokes in binary files on the device (.rm files, also called lines format). For backup and/or conversion jobs, it can be helpful to parse this binary format.

Kaitai Struct is a declarative parser specification language for binary data formats, and an accompanying parser generator. Kaitai Struct specifications can be compiled to code for a parser in one of various languages. It also has serialization capabilites, although they are currently limited to few languages.

This repository contains a Kaitai Struct specification for some versions of the reMarkable lines (.rm) format.

Notes

This specification was made very quickly for fun, and it could probably be improved.

The specifications have only been tested superficially. Version 6 of the specification has only been tested on documents prepared in the xochitl app version 3.8.2.

The reMarkable lines format evolves as the reMarkable receives updates, and this repository is not going to be kept up to date. Forks are welcome.

Contents

• rm_v3.ksy - spec for reMarkable lines format, version 3
• rm_v5.ksy - spec for reMarkable lines format, version 5
  • hello_v5.rm - example v5 lines binary file
• rm_v6.ksy - spec for reMarkable lines format, version 6
  • leb128.ksy - spec for Little Endian Base 128 which is used in lines format, version 6
  • hello_v6.rm - example v6 lines binary file
• rm_v6.hexpat - ImHex pattern for lines format, version 6
  • included to make further development of the kaitai spec easier

Credits

• Thanks to ax3l for documenting a thorough exploration of the binary format, and for the C++ and Rust reference implementations of the parser.
• Thanks to reHackable's awesome-reMarkable project, which brings together many great and open projects for enhancing the reMarkable notebook experience, and helped me find ax3l's work.
• Thanks to a stackoverflow answer for informing me about Kaitai Struct, saving me from writing a parser in Python (I use Python too much, and should really branch out more).
• Kaitai Struct was super easy to pick up due to the great documentation and online IDE. Thanks, for helping me feel like a hacker!
• Thanks to reMarkable AS for your awesome tablet. It is a technology that has an unquestionably positive impact on my life (and in case anyone hasn't noticed, that's saying something for a technology these days).
• Thanks to rM Hacks discord server for pointing out there's an env variable SCENE_FILE_V6_DEBUG which made the process of analyzing binary format much easier.

This repository is not affiliated with reMarkable AS.