GoKawiilImHex creator publishes guide to reverse-engineering FEZ's binary save format
The developer behind the ImHex hex editor wrote a tutorial demonstrating how to reverse-engineer an undocumented binary file format, using the 2012 game FEZ's save file as the example. The walkthrough shows how to move from raw hex bytes to a complete structure definition written in ImHex's Pattern Language, a feature available on the free, open-source, cross-platform tool.
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Proprietary and undocumented save or data formats are common obstacles for modders, archivists, and researchers trying to preserve or extend older software. By turning a real-world example into a step-by-step method, this guide gives the reverse-engineering community a repeatable process rather than ad hoc guesswork, lowering the barrier for others to document obscure file formats themselves.
- ImHex's Pattern Language lets users formally define and parse unknown binary file structures.
- The tutorial uses FEZ's 2012 save file as a concrete case study, including spoiler-heavy game data.
- Some functionality demonstrated requires ImHex's Nightly build rather than the latest stable release.
Practical Binary Analysis (No Starch Press book) — If picking apart FEZ's save file in ImHex gave you the bug, this No Starch Press book is the natural next step, covering binary formats, disassembly and instrumentation in depth. It pairs perfectly with a hex editor and pattern language work, teaching you how to reason about unknown data from the ground up.
See Practical Binary Analysis (No Starch Press book) on Amazon → Affiliate link — we may earn a commission on purchases, at no extra cost to you. Product picked by AI based on this article; it is not a tested recommendation.Source: werwolv.net, 2026-08-31
Published there as: “Reverse Engineering Unknown File Formats with ImHex”
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