TerraFirmaGreg Modern: a GregTech and TerraFirmaCraft modpack for Minecraft 1.20.1

What the pack is trying to fuse

TerraFirmaGreg Modern is described as a deep survival and tech modpack for Minecraft 1.20.1 that seamlessly fuses together TerraFirmaCraft and GregTech, and the readme frames it as a technological journey starting by banging rocks together, taming an untouched wilderness into an industrial wonderland, and ending with control over the very stars.

The readme then lists the audiences it is trying to reach, which is a fairly honest set of pitches. A player looking for a longer modpack where every step feels rewarding and you are constantly building on previous technologies. A player who wants every mod carefully integrated rather than just thrown in. Someone who dislikes magic mods, or who wants a tech modpack that feels less Minecrafty with its automation. Or someone who just wants to try out GregTech without losing years of their life.

That last one is the interesting framing, because it tells you the pack's real design problem. GregTech on its own is famously long, and TerraFirmaCraft on its own is famously slow. Running them in parallel doubles the grind unless something makes the two progressions feed each other.

The heart of the pack is therefore the integration between the two namesake mods. TerraFirmaCraft is described as a total overhaul mod renowned for its immersive survival mechanics, and GregTech Modern as an expansive tech mod famous for its realistic chemistry and deep, complex progression.

On top of those, other major mods add depth. Create and Greate let you automate problems away early with Create's kinetic machines, integrated through Greate. Ad Astra is marked as work in progress and is there to grow the factory further beyond, with new logistic and survival problems to solve. Applied Energistics 2 provides large-scale storage and automation appropriate for an advanced era.

The readme also claims that many new mechanics, tools and dimensions are built completely from the ground up just for TerraFirmaGreg, and that smaller mods and addons tie everything together, with an in-game book and quest system providing the information a player needs.

The repository, and the tooling that assembled it

The repository listing gives a good picture of how the pack is built and maintained, and the tool names are the interesting part.

There is a .pakku/ directory along with pakku.json and pakku-lock.json and a pakku.jar at the root. Pakku is a modpack build tool for Minecraft, and having a lock file alongside the jar is the mark of a pack whose dependency set is pinned and reproducible rather than hand-maintained. That is a meaningful difference from the older generation of modpacks where a manifest file listed versions and nothing checked that they resolved.

There is also a kubejs/ directory, which is the mod that lets a pack ship its own JavaScript-driven recipes and behaviours without compiling a mod, and a tacz/ directory for a weapon and ammunition mod. The config/ and defaultconfigs/ directories separate the pack's own configuration from the per-world configuration, a distinction that matters because defaultconfigs/ is applied to new worlds and config/ overrides it.

There is a .devcontainer/ directory, so contributors work in a containerised environment rather than needing a locally installed Minecraft toolchain, and a .github/ directory for the workflows. The .gitattributes file is there for line-ending handling, which matters for a repository with configuration files that are compared line by line.

There is a CHANGELOG.md, which for a pack that ships updates constantly is the document a player actually reads before updating, and a LICENSE file, with the project recorded as LGPL-3.0.

The primary language is listed as JavaScript, which is consistent with the kubejs/ directory and the scripts that make the pack's own mechanics work. The default branch is dev, so the development branch is where the work happens, and the releases are versioned separately.

The distribution point is CurseForge, at the modpacks page for terrafirmagreg-modern, and the project also runs a Discord server and a wiki at wiki.terrafirmagreg.team.

Updates, world compatibility and the two support routes

The development section is short and it contains the promises a player cares about.

The modpack is still a work in progress and is constantly being updated. In its current state, the modpack is fully completable, and worlds will always be compatible with future versions. Clear instructions will be provided if you need to take any extra steps when updating.

That last sentence is the one to read carefully. The compatibility claim is a commitment that worlds survive updates, and the qualifier is that when an update requires something from the player, instructions will be provided. For a pack that adds its own recipes, its own mechanics and its own dimensions, that qualifier is doing real work. A pack that rewrites recipes between versions can invalidate a world, and the way to avoid promising more than can be delivered is to promise compatibility and then publish the steps for the cases that need them.

The claim that the pack is fully completable in its current state is the other thing to weigh. It means the progression chain works end to end today, which is the meaningful guarantee for someone about to spend dozens of hours in it, and it also means new content is being added to a world that is already finished.

There are two support routes for contributors, and they are separate. For code, the wiki has a contributing page with setup instructions, coding standards and guidelines. For translation, the project uses Crowdin, with a link to the project's Crowdin page, and translations are therefore managed as a continuous localisation workflow rather than as pull requests against translation files.

The readme links the wiki, the issue tracker for both bugs and feature requests, a project board on GitHub for the roadmap, and the Discord server.

Where TerraFirmaGreg Modern is the wrong choice

The first limitation is the work-in-progress status, stated by the project itself. A pack that is constantly being updated and that is fully completable in its current state is two things at once: it is playable today, and it will keep changing under you. The promise of world compatibility is what makes that survivable, and it is a promise from the team rather than a technical property of Minecraft, so the practical test is whether the changelog for the version you are updating to describes anything that affects your base or your machines.

The second is the Forge dependency. The topics list forge, and the pack is built on it, so it cannot be run on Fabric without the ports existing, and the add-on ecosystem available depends on the loader. That is a constraint every large modpack carries and nobody minds until they want to mix it with a Fabric-only mod.

The third is the load and the length. This is a deep survival and tech pack combining two of the most demanding Minecraft mods, with Create, Greate, Applied Energistics 2 and Ad Astra on top, plus an ingame book and quest system. A machine with modest memory will struggle, and a player who wants to try GregTech for a week will find the pace is the point of the pack rather than a feature to skip.

The fourth is the dependency on two upstream mods with their own release cadences. TerraFirmaCraft and GregTech Modern both ship on their own schedules, and the pack has to hold them at compatible versions. When one of them moves, the pack's pakku lock file changes, and the player updates two things at once even if only one of them changed.

The fifth is that Ad Astra is marked as work in progress, and the pack itself is marked as work in progress. The readme's ambition, ending with control over the very stars, is a direction rather than a description of the current content, and the dimension content in particular may still be in flux.

Editorial conclusion

TerraFirmaGreg Modern fits a Minecraft player who wants a long technical playthrough where the factory side and the survival side pull on each other, since the pack's premise is that GregTech progression and TerraFirmaCraft's hunger, temperature and tool-wear mechanics advance together rather than in sequence. It is the wrong choice if you want a finished, stable pack, since the readme states the modpack is still a work in progress and is constantly being updated, and it is the wrong choice if you dislike magic mods or want something that feels less Minecrafty. Before installing, read the wiki page on updating worlds, since the pack promises world compatibility but says clear instructions will be provided if extra steps are needed, and note that the last push was on 2026-10-20 with version 0.13.14 released on 2026-10-19.

Frequently asked questions

Official sources

1. License: LGPL-3.0
2. Project website
3. README
4. Releases
5. TerraFirmaGreg-Team/Modpack-Modern on GitHub