01Choose the Linux package for your distribution
Release v3.2.19 publishes five Linux formats from one build: r2modman-3.2.19.AppImage at 200,488,834 bytes (about 191 MB), r2modman_3.2.19_amd64.deb at 154,752,116, r2modman-3.2.19.x86_64.rpm at 139,615,825, r2modman-3.2.19.pacman at 141,597,372, and r2modman-3.2.19.tar.gz at 192,564,743. Take the AppImage for a portable install that ignores your distribution, the deb on Debian and Ubuntu, the rpm on Fedora or openSUSE, and the pacman package on Arch. The tar.gz is a plain archive for manual extraction when no package format fits your system. Every format drives the same profiles, config editor, and Start modded behaviour — the choice only changes how the application is installed, updated, and removed.
02Make the AppImage executable and run it
The r2modman Linux AppImage arrives without the execute bit, so a double-click in a file manager can do nothing at all. Keep it in a directory you own, such as ~/Applications, then start it once from a terminal so a launch error stays on screen instead of vanishing with a desktop launcher. There is no installer and no package manager entry: deleting the file uninstalls the application. Keep the AppImage outside Steam libraries and game directories. If the manager fails to start, the documented first check is the --no-sandbox flag, which points at the Electron sandbox rather than at a bad download or a missing library.
chmod +x ~/Applications/r2modman-3.2.19.AppImage
~/Applications/r2modman-3.2.19.AppImage
03Install the Flatpak remote so updates stay small
As of v3.2.19 the Flatpak is published to a remote repository, so it updates like any other Flatpak application instead of being replaced by hand, and a Flatpak update is far smaller than downloading a fresh 191 MB AppImage. The app ID is io.github.ebkr.r2modman. r2modman is not on Flathub, so it comes from its own r2builds remote. Pick one of the two blocks below and stay with it: Flatpak registers remotes per installation, so a per-user install cannot see a remote added system-wide, and mixing the two fails with a remote that cannot be found. The standalone r2modman.flatpak asset is 142,481,440 bytes, about 136 MB, if you need an offline install. Because the remote is registered once, later versions arrive through the normal flatpak update path against the r2builds remote, with no manual file handling.
# system-wide, one password prompt
sudo flatpak remote-add --if-not-exists r2builds https://r2builds.ebkr.dev/flatpak/r2modman.flatpakrepo
sudo flatpak install r2builds io.github.ebkr.r2modman
# per-user, no password
flatpak remote-add --user --if-not-exists r2builds https://r2builds.ebkr.dev/flatpak/r2modman.flatpakrepo
flatpak install --user io.github.ebkr.r2modman
04Fix Proton games detected as native Linux
A known bug makes the manager treat Proton games as native Linux titles, which produces invalid launch instructions and a failure to start the game modded. It is tracked as issue #950 with a fix in #952. The quickest workaround is an empty file named .forceproton at the root of the game install directory — the folder holding the game executable. The alternative is to correct the game’s Steam config: open ~/.steam/steam/steamapps/appmanifest_632360.acf (Risk of Rain 2’s App ID) and add platform_override_dest “linux” and platform_override_source “windows” inside the UserConfig block, leaving the language line alone. Restart the manager, which re-reads that config only at startup.
05Use r2modman when Steam is itself a Flatpak
A sandboxed Steam cannot hand its environment to an AppImage, so add the AppImage as a non-Steam game and give it the launch options --appimage-extract-and-run --no-sandbox; the sandbox flag is required because of AppArmor restrictions on Electron applications. Then point r2modman at the sandboxed locations. The game directory resembles /home/steam/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/common/ATLYSS, and the Steam directory resembles /home/steam/.local/share/Steam. Verify both fields in Settings → Directories afterwards, because a sandboxed Steam exposes a different prefix than a native install. Add the blank .forceproton file inside the game folder as well if the Proton detection bug applies.
06Prove the modded launch on Linux
Start modded is the only real confirmation that the whole chain works on your distribution. Select the game, check Settings → Directories against Steam’s Browse local files result, create a fresh profile, install only the loader — the package carrying the blue Pinned tag on the Online tab — and launch. If that succeeds, the manager, path detection, and loader handoff are all functioning and you can add mods in small batches. When the game exits immediately, the first loader exception is more useful than the final line of the log. Launching through Steam runs the unmodded build by design, which is a useful control after a SteamOS or Proton update.
07Work around Wayland and display quirks
Electron support for Wayland remains uneven, and some desktops — COSMIC is a documented example — struggle with the zypak helper, leaving the manager window blank or refusing to open at all. Running the Flatpak under X11 with GPU acceleration disabled is the known workaround. Steam Deck uses Wayland only in Desktop Mode, and the AppImage does not show the same symptom there, so treat these flags as a diagnostic step rather than a permanent configuration. If the window opens but stays black, the same combination of an X11 ozone platform and a disabled GPU usually settles it.
flatpak run io.github.ebkr.r2modman --ozone-platform=x11 --disable-gpu
08Know the manager’s compatibility limits
r2modman hides other mod managers from its listings and applies a short exclusion list, and DekuDesu-BetterHud is a documented incompatible mod. Where a game ships both a native Linux build and a Windows build, note which one the profile targets, because the two install into different directories and a Proton prefix is not interchangeable with the native one. Beyond that, multiplayer needs matching packages and versions on every client, and server or anti-cheat rules apply regardless of what loads locally. A loader working on Windows says nothing about its behaviour under Proton.
✦ Frequently asked questions
Common questions, answered directly.
Should I use the AppImage, the deb, or the Flatpak?
The Flatpak is the best fit if you want updates handled by flatpak from the r2builds remote. The deb, rpm, and pacman packages integrate with your distribution’s package manager. The AppImage needs no installation at all and is the simplest way to test a second version beside your main one.
Why does the AppImage do nothing when I open it?
Grant the execute bit with chmod +x first, then launch the file from a terminal to capture the first error message. If that message concerns the Electron sandbox, --no-sandbox is the documented diagnostic step, but treat it as evidence of a permission problem rather than a permanent setting.
Does r2modman work with Proton games?
It can, but a known bug makes the manager treat Proton titles as native Linux games, which breaks the modded launch. Create an empty .forceproton file at the root of the game install directory, or add the platform override lines to the game’s appmanifest .acf file, then restart the manager.
How do I update r2modman on Linux?
With the Flatpak, run a normal flatpak update against the r2builds remote, which pulls a small delta rather than a whole new application. With the AppImage, download the new asset — currently r2modman-3.2.19.AppImage — replace the old file, and restore the execute permission. The native deb, rpm, and pacman builds use r2modman’s updater with the corresponding system package tool and can request administrator approval while they install.
Can I run r2modman when Steam is a Flatpak?
Yes. Add the AppImage as a non-Steam game with the launch options --appimage-extract-and-run --no-sandbox, then set the game path under .var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/common and the Steam path to /home/steam/.local/share/Steam. Add the blank .forceproton marker inside the game folder if that title needs it. Verify both values in Settings → Directories before installing anything, because a sandboxed Steam exposes a different prefix than a native install.
Every release keeps the assets, byte sizes and SHA-512 digests it was published with, so an older build can still be matched against its original metadata.
Next: download or update the current build, keep one profile with only the loader enabled, confirm a modded launch from Start modded, then add the rest of your mods in small batches.