Cinderbox Companion

A companion app for Stardew Valley on Android. Syncs save files with Steam Cloud, downloads game files, and manages SMAPI mods — all from your phone.

Works with both the official Android port and Cinderbox (the modded Android client).

This is an independent fan project. It is not affiliated with, endorsed by, or connected to ConcernedApe, Chucklefish, or the Cinderbox developers. Stardew Valley is a trademark of ConcernedApe.

Important Warning Use this app at your own risk. I have limited experience with Stardew Valley modding and cannot guarantee how syncing, downloading, or mod management will affect your save files.

Always back up your saves before using this app. The app creates automatic backups during sync, but you should also keep your own copies in a safe location.

I am not responsible for any loss of save data, corrupted files, or damage to your device that may result from using this app. If something goes wrong with your saves, having a manual backup is the only reliable way to recover them.

Features Steam Cloud Sync — Pull saves from Steam Cloud to your device, or push local saves back. Conflict detection tells you which version is newer before you overwrite anything. Game File Download — Download Stardew Valley game files directly from Steam using your own account. Supports branch selection and file verification. Cinderbox Setup Wizard — Guided setup for Cinderbox: handles permissions, downloads the APK, walks you through installation, and verifies everything is ready before downloading game files. SMAPI Setup — Extracts SMAPI internals to the correct location so mods can load. Mod Manager — Browse Nexus Mods, download, install, update, and manage SMAPI mods and content packs directly from the app. Requires a free Nexus Mods API key. Multiple File Access Methods — Supports Root, Shizuku, All Files permission, SAF, and manual staging to access save files across different Android versions and device configurations. Auto-Sync — Optionally push saves to Steam Cloud automatically when the game closes (requires root).

Android Version Compatibility The app works best on Android 13 and below, where file access to the game's save directory is straightforward.

Android 14+ introduced stricter file access restrictions that prevent apps from reading /Android/data/ directly. Workarounds:

Rooted device — Full access with no restrictions. Shizuku — Grants elevated file access without root. Install Shizuku from the Play Store and start it via ADB or wireless debugging. Manual file transfer — Use a file manager that still has access to /Android/data/ (such as ZArchiver, MT Manager, or MT2) to manually move saves between the game directory and a staging folder. The app's SAF staging mode supports this workflow. Cinderbox mode — Cinderbox stores saves in /storage/emulated/0/StardewValley/Saves/ instead of inside /Android/data/. This path remains accessible with the standard All Files permission even on Android 14+, avoiding the stricter restrictions that apply to app-private directories.

Getting Started Download the latest APK and install it. Log in with your Steam account. Steam Guard (2FA) is supported — you can sign in with a code or scan a QR code from the Steam mobile app. Sync saves — The Saves tab shows all your Steam Cloud saves. Pull them to your device or push local saves back to the cloud. Download game files (optional) — If you need game files for Cinderbox (or something like Winlator), go to the Download tab. The setup wizard will guide you through the full process.

File Access Setup On first use, the app auto-detects the best available method to access save files. You can change this in Settings under "File Access". The available methods depend on your device:

Method Requires Android Version Root Rooted device All Shizuku Shizuku app running All All Files MANAGE_EXTERNAL_STORAGE permission 11–13 (may not work on 14+) SAF User-selected directory All (staging mode on 14+) Manual File manager