Majora's Mask Decomp: 100 Percent on the Badge and Still a Work in Progress

By Indie Kings | October 28, 2026

Updated October 28, 2026: zeldaret/mm, the decompilation of The Legend of Zelda: Majora's Mask, reports 100 percent on its own progress badge while its README still opens with a work in progress warning, and its newest commit, dated October 21, 2026, documents the EnInsect actor. The repository supports only the US 1.0 Nintendo 64 release, builds both a standard and a compressed ROM, and has drawn 83 contributors since March 2020.

Image: a Nintendo 64, the hardware Majora's Mask shipped on, via Wikimedia Commons.

What the 100 percent badge means

The project's progress badge, served from zelda.deco.mp, reports 100 percent. The README, in the same repository, carries a warning that the codebase is a work in progress, that it can change drastically at any time, and that some parts of the ROM may not be shiftable yet. Both statements are true, and understanding why is the key to reading decompilation progress in general. A matching decompilation can reach full coverage of the game's code while still being an evolving repository, because the remaining work shifts from converting unknown functions into C to naming things correctly, documenting structures, and making every piece of the ROM safe to move.

Shiftability is the technical heart of that distinction. If a routine is matched but still hardcoded to a fixed address, editing it in a way that changes its size breaks everything that references the old location. Projects spend years converting matched code into relocatable code, which is why a 100 percent badge and a warning label coexist without contradiction. For a modder, the badge says the source is complete enough to read; the warning says the linker map may still fight back. For everyone else, it is a useful corrective to the idea that decompilation ends when the percentage hits three digits.

One version, on purpose

The README states that the only supported version is the US Nintendo 64 release, and that the team intends to eventually support every retail version of the original game, explicitly excluding Majora's Mask 3D, which it calls a totally different game. That scope decision is deliberate. Majora's Mask shipped in fewer regional variants than Ocarina of Time, so supporting one version first gets the project to a usable state sooner, and the Japanese and European releases can follow once the core work is stable. The 3D remake is a different codebase entirely, so pretending it belongs in the same repository would only confuse the matching effort.

The build produces two files: mm-n64-us.z64 with MD5 f46493eaa0628827dbd6ad3ecd8d65d6, and mm-n64-us-compressed.z64 with MD5 2a0a8acb61538235bc1094d297fb6556. The compressed variant matters because the retail cartridge stored its data compressed, and a decompilation that only produced an uncompressed image would not be reproducing the cartridge. Publishing both hashes gives contributors two verification targets and documents the compression step as part of the build rather than an afterthought. The README also states plainly that the repository includes no assets or assembly code and that a prior copy of the game is required to extract what the build needs.

Documentation as the remaining work

The October 21 commit documents the EnInsect actor, one of the game's small creature actors. That is exactly what late stage decompilation looks like: not a dramatic feature, but a named structure with explained fields, added by someone who read the assembly and worked out what each value does. Every commit of this kind makes the codebase more useful to the next person, and the numbering, pull request 1861, shows how many such changes have accumulated since the repository was created on March 17, 2020.

Eighty three contributors and 11 open issues round out the picture of a mature project. The open issues are few enough to read individually, the fork count of 599 is high relative to the star count of 1,765, and the activity is steady rather than frantic. Majora's Mask is also a game whose internals are unusually interesting to modders because of its three day cycle and its event flag system, so a documented source tree has value beyond preservation. The repository is not finished, and it says so, but the distance remaining is measured in names and comments rather than in unknown functions.

Project card

FAQ

Is the Majora's Mask decompilation finished?
Its progress badge reports 100 percent, but the README still describes it as a work in progress with parts of the ROM that are not shiftable. Finished coverage and finished documentation are different milestones.

Which version does it support?
Only the US Nintendo 64 1.0 release for now, with other retail versions planned. Majora's Mask 3D is explicitly out of scope.

What does it build?
A standard ROM, mm-n64-us.z64, and the compressed variant that matches the retail cartridge's storage format.

Do I need the game to build it?
Yes. The repository contains no assets or assembly, and the README requires a prior copy for extraction.

What was the October 2026 change?
A commit documenting the EnInsect actor, adding names and explanations for a small enemy's data structures.

Can I mod the game with it?
Yes, with the README's caveat that the codebase can change drastically and that non shiftable ROM sections make some modifications difficult.

Bottom Line

The most honest thing about this project is the gap between its badge and its warning, because that gap is where most decompilation work actually lives. Majora's Mask has been fully covered for years, and the team is still documenting actors one commit at a time, which is the difference between a codebase that compiles and a codebase that teaches. With 83 contributors and only 11 open issues, the project is closer to a reference document than a rescue operation, and the compressed ROM target is a reminder that matching the cartridge means matching its storage decisions too.

Sources

• GitHub zeldaret/mm README, version scope, build outputs and hashes, asset notice, accessed October 28, 2026
• zelda.deco.mp progress badge endpoint for Majora's Mask, accessed October 28, 2026
• GitHub API metadata for zeldaret/mm, stars, forks, contributors, issues and latest commit, accessed October 28, 2026

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