If you uninstall an emulator or reset the device, you can easily lose hundreds of hours of saves.

With a simple setup you can make your entire retro collection portable and easy to back up or move to a new device. This guide focuses on:

• AYN Odin 2 Portal
• Retroid Pocket (Android-based models)
• RetroArch + standalone emulators
• Optional Syncthing setup for automatic backups

Core idea: SD card as the “library”

Android apps can be wiped at any time. Your microSD card usually isn’t.

The core strategy:

1. Use a microSD card as your main library for ROMs, saves, and configs.
2. Configure emulators so that:
   • ROMs are loaded from the SD card.
   • Saves and, where possible, configs live on the SD card or in clearly visible folders.
3. Back up that SD card (and a couple of internal folders) to your PC or NAS regularly.

Once that’s in place you can uninstall emulators, factory reset the handheld, or move to a new device and keep all your progress intact.

Folder structure on the SD card

You do not need anything fancy. Something like this is enough:

/storage/XXXX-XXXX/Games/
  roms/
    nes/
    snes/
    gba/
    ps1/
    ps2/
    gc/
    wii/
    switch/
    ...
  saves/
  states/
  configs/
    retroarch/
    eden/

Where:

• XXXX-XXXX is your SD card ID.
• roms/ contains all game files, sorted by system.
• saves/ and states/ are optional if you prefer to keep saves separate.
• configs/ can store emulator config files and front-end data if you choose to externalize them.

Adjust the structure if you like, but pick something and stick to it.

RetroArch: the easy part

Most systems (NES, SNES, GBA, PS1, etc.) will typically run through RetroArch.

Default behavior that helps you

On Android, RetroArch’s default setting for saves is:

• Savefile = “Content directory”
• Savestate = “Content directory”

That means:

Save files and save states go into the same folder as the ROM.

If your ROMs are on the SD card, your RetroArch saves and states are also on the SD card by default. You do not need to change anything for safety.

You can verify this quickly:

1. Load a ROM from your SD card in RetroArch.
2. Save in-game and/or create a savestate.
3. Check that ROM’s folder on the SD card; you should see files like .srm, .sav, .state.

That alone gives you per-game saves living next to the ROM and simple backup: copy the ROM tree and you also get the saves.

Optional: centralized RetroArch saves on SD

If you prefer a cleaner structure, you can centralize RetroArch saves on the SD card:

1. Open RetroArch → Settings → Directory.
2. Set:
   • Savefile → /storage/XXXX-XXXX/Games/saves/
   • Savestate → /storage/XXXX-XXXX/Games/states/
3. Optionally:
   • Config → /storage/XXXX-XXXX/Games/configs/retroarch/
   • Playlist, Thumbnails similarly under configs/retroarch/.
4. Go to Main Menu → Configuration File → Save Current Configuration.

This does not change the safety principle. It just makes backups more organized.

Switch: Eden (Yuzu fork) on Android

Switch emulation is the outlier in most setups.

Eden (a Yuzu fork) stores Switch saves inside a NAND directory. By default this lives in app data. If you uninstall Eden without moving it, you lose saves.

On Android builds of Eden there is a setting for this:

Configuration → System → File system → NAND directory

Safer setup for Eden on SD

Ideal setup on SD:

1. Create a folder, for example:

   /storage/XXXX-XXXX/Games/configs/eden/nand/

2. In Eden, go to:
   • Configuration → System → File system → NAND directory
   • Point it to the folder above.
3. Keep your Switch games under:

   /storage/XXXX-XXXX/Games/roms/switch/

Result:

• All Eden user data and saves live on the SD card.
• Uninstalling Eden no longer touches saves.
• You can back up or move the entire Switch setup by copying:
  • Games/roms/switch/
  • Games/configs/eden/

If you do not want to move the NAND, at minimum you should periodically copy the existing NAND folder (from Eden’s user data path) to your PC.

Dolphin, Citra, PPSSPP, and other standalone emulators

If you mostly use RetroArch cores, you can ignore standalone emulators for those systems. The only ones you care about are the standalone apps you actually use.

Typical defaults on Android:

• PPSSPP (PSP)
  • Uses a visible PSP/ folder on shared storage.
  • Back up the entire PSP/ folder to capture ROM lists, saves, and states.
• Dolphin (GameCube / Wii standalone)
  • Typically uses dolphin-emu/ or a “User data” directory for configs and saves.
  • Back up that whole folder.
• Citra (3DS)
  • Uses a citra-emu/ folder or an Android/data/.../files user directory.
  • Copy that directory to capture saves and configuration.
• AetherSX2 / PS2 forks
  • Store memory card files and save states under their user folder, usually inside Android/data/.../files.

On recent Android versions, Android/data is restricted. For those, either use a file manager that can access it (X-plore, Solid Explorer) or use each emulator’s built-in export/transfer tools to move saves into a visible folder and then back that up.

If you are using RetroArch cores instead of standalone versions, you can skip these entirely and just care about RetroArch + Eden.

AYN Odin 2 Portal workflow

Putting it together for the Odin 2 Portal:

1. Install a good microSD card (U3 / A2, 256–512 GB).
2. On the SD card, create:

   /storage/XXXX-XXXX/Games/
     roms/
     saves/
     states/
     configs/
       retroarch/
       eden/
   

3. Put all ROMs for RetroArch cores (and the Dolphin core) under roms/ by system.
4. Use RetroArch for everything except Switch games.
5. For Eden:
   • Set the NAND directory to /storage/XXXX-XXXX/Games/configs/eden/nand/.
6. If you use any extra standalone emulators, either:
   • Move their user directories to SD where supported, or
   • Periodically copy their internal user folders to your PC.

Backups then become:

• Remove the SD card, plug into a PC, copy /Games/ to your backup location.
• Optionally also copy any remaining emulator data folders from internal storage.

Retroid Pocket (Android-based)

The same principles apply to Android-based Retroid Pocket devices:

• They also support microSD expansion.
• Their frontends often auto-create a structure on the SD card for ROMs.

On Retroid:

1. Let the Retroid launcher create its ROM directories on the SD card, or create your own /Games/roms/ tree.
2. Point RetroArch to load ROMs from the SD card.
3. Keep RetroArch in its default “save to content directory” mode, or centralize on SD as described earlier.
4. For standalone emulators (PPSSPP, Dolphin, etc.) either:
   • Use their default external folders (PSP/, dolphin-emu/), or
   • Move their data paths to SD where possible.

Backup routine:

• Remove the SD card and copy the entire games structure to your PC or NAS.
• Optionally also copy any internal emulator user folders if they hold configs or saves you care about.

Keeping everything standardized under something like /Games/ means you can reuse the same SD card (and backups) between devices: Odin, Retroid, or even an Android tablet.

Backups with Syncthing (optional)

If you want automatic, continuous backups instead of manual SD card copies, Syncthing is a good option. It works across PCs, NAS, and Android handhelds.

What Syncthing does

• Syncs folders between devices over your local network or the internet.
• Works peer-to-peer; no central cloud service required.
• Can be set to “send-only” on the handheld so changes only flow out, not in.

Setup overview

You need Syncthing running on:

• Your Odin 2 Portal / Retroid Pocket (Android app).
• Your PC or NAS (desktop/server build).

1. Install and pair devices

1. Install Syncthing on the handheld.
2. Install Syncthing on your PC or NAS.
3. Open Syncthing on both and:
   • Add each device’s ID on the other side.
   • Approve the connection.

Now they trust each other and can sync folders.

2. Choose which folders to sync

On the handheld, add a Syncthing folder:

• Path: /storage/XXXX-XXXX/Games/
• Folder type: usually Send Only from the handheld’s side.

On your PC/NAS, map it to a local path, for example:

D:\Backups\Odin2\Games\

If you still have any important emulator folders on internal storage that you want synced (for example an internal NAND that you haven’t moved yet), you can add those as additional Syncthing folders.

3. Limit when it syncs

To avoid battery drain and mobile data usage, configure Syncthing to:

• Sync only on Wi-Fi.
• Optionally sync only while charging.
• Optionally keep a small number of older versions if you want rollback safety.

Once configured, Syncthing will notice changes in /Games/ on the handheld and sync them to your PC/NAS whenever the conditions are met.

When Syncthing makes sense

Syncthing is a good fit if:

• You play often and don’t want to think about backups.
• You have a PC or NAS that is frequently on.
• You want restores and migrations to be as simple as plugging in a new SD card and installing your emulators.

If you only update your library occasionally and prefer simplicity, manual SD card backups might be enough.

Minimal checklist

If you want the shortest possible version:

1. Put ROMs on SD under a clear folder tree (for example /Games/roms/...).
2. Use RetroArch for everything non-Switch.
   • With ROMs on SD, saves are automatically on SD as well.
3. For Switch (Eden):
   • Set the NAND directory to a folder on the SD card, or
   • At least periodically copy the NAND folder to your PC.
4. Backups:
   • Either:
     • Remove SD → copy /Games/ to PC/NAS, and
     • Copy any remaining emulator data folders from internal storage.
   • Or:
     • Use Syncthing to keep /Games/ continuously synced to your PC/NAS.

With that in place, factory resets, emulator reinstalls, and device upgrades stop being risky. Your ROMs, saves, and configs are just data, neatly stored and backed up.