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FermiumBooter

Simplistic mixin mod utility to allow developers to load mixins both early and late

Forge
Loaders
Forge
Downloads on Modrinth
320K
Followers on Modrinth
4
versions
14
Updated
October 22, 2026Oct 22
Published
in 2024
This is a library — other mods need it, and it adds nothing to the game by itselfRequired by 22 mods. Download it if another mod needs it.

At a glance

A library: other mods need it — required by 22 mods
Runs on Forge
For Minecraft 1.12.2
Works on either side — install it in the game, on the server, or both
Latest version — 1.6.2 from October 22, 2026
License LGPL-3.0-or-later — free
Where it's needed
In gameoptionalOn serveroptional

Works both in the game and on the server — install where you need it

Game versions1.12.2

FermiumBooter is a mixin mod utility to allow developers to load mixins both early and late, allowing for modifying classes that normally could not be modified otherwise.

Current features include;

  • Enqueue mixins to be applied both early and late, to allow for for modifying Vanilla/Forge classes, as well as mod classes
  • @MixinConfig annotation system to expand on the Forge @Config system, to allow for automatic mixin enqueue based on config toggles
  • Optional compatibility handling through the config annotation system to allow developers to define required/incompatible mods for specific mixins
  • Logged warnings when a mixin using the config annotation system fails compatibility checks
  • Optional forced mixin disabling when a mixin using the config annotation system fails compatibility checks
  • Ingame (disable-able) warning rendering when mixins using the config annotation system fail compatibility checks
  • Enable/disable enqueued mixins prior to application through the use of a Supplier, to allow developer control over optional mixins
  • Utility method to check if a ModID is present similar to Loader.isModLoaded() however usable during mixin enqueue/early mixin application unlike Loader.isModLoaded()
  • Disallow other FermiumBooter enqueued mixins from applying, for testing or tweaking purposes

  • Shadows Mixin 0.8.7 and MixinExtras 0.4.1

For developer usage:

In your IFMLLoadingPlugin init, instead of "Mixins.addConfiguration("mixinConfigName")", use "FermiumRegistryAPI.enqueueMixin("mixinConfigName").
If you are registering it as a late-loaded mixin use "FermiumRegistryAPI.enqueueMixin(true, "mixinConfigName")".
That is all that is required, and FermiumBooter takes care of the rest.
For additional utilities as described previously, all are documented in code with explanations of usage and purpose.

If you have any issues/suggestions/requests, please post them to the Github issue tracker linked above.

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FAQ

How to install FermiumBooter?

Install Forge for your Minecraft version, download FermiumBooter for the same version and loader, put the file into the mods folder and launch the game with the loader profile.

Which Minecraft versions does FermiumBooter support?

FermiumBooter has builds for Minecraft 1.12.2.

Is FermiumBooter needed on the server?

Works on either side — install it in the game, on the server, or both

License and source
GNU Lesser General Public License v3.0 or laterfree to use and share; changes to the mod itself must be published under the same license
Original — Modrinth↗Files unchanged, verified with SHA-512Is this your mod? For rights holders

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