Quick answers to the questions handheld owners ask most. If your question is not here, the linked pages go into more depth.
How do I change the screen brightness?
Hold Select and press Vol + to brighten or Vol - to dim. This works everywhere, in the menus and inside games.
You can also set brightness under Settings > Display Settings > Brightness, or from the Quick Menu (hold Power).
How do I open the RetroArch menu or exit a game?
Inside a RetroArch game, GammaOS drives everything from the Back button:
- Tap Back once to open the RetroArch menu.
- Hold Back to exit back to the Nano home. You land back on the same game.
- L3 + R3 (click both sticks in) also opens the RetroArch menu.
This is the RetroArch Back Button Override. Full details are on the RetroArch Controls page.
How do I exit a DS (DraStic) game?
Hold the Back button. The same hold-to-exit that quits RetroArch also quits DraStic Nano and returns you to the home. See DraStic Nano for more.
My games do not show up
Work through this checklist:
- Put your ROMs in the right per-system folder, for example
/sdcard/ROMs/nes/for NES or/sdcard/ROMs/snes/for SNES. SD card, internal storage, and USB all work. - Go to Settings > Game Settings > Rescan Games.
- Check the system is enabled in Settings > Game Settings > Game Systems (each system has an On/Off toggle).
- Make sure your file types match the system's Extensions list. For example, SNES expects
.smc,.sfc,.fig, or.swc.
If your games are inside subfolders, turn on Scan ROM Subfolders in the GammaOS Toolbox, then rescan. See Adding Games for the full guide.
A game will not launch
The most common causes:
- Missing BIOS. GammaOS does not ship console BIOS or firmware files. Systems like PlayStation, PS2, Dreamcast, and Neo Geo need you to supply your own. For RetroArch cores, put BIOS files in
Internal storage / RetroArch / system. Standalone emulators (AetherSX2, PPSSPP, Flycast) each have their own first-run BIOS import step. Nintendo DS games are the exception and need no BIOS. - Wrong core or package. Check the Emulator set for that system in the Game Systems editor.
- Wrong extension. The game's file type must be in that system's Extensions list.
Games that need a BIOS will not launch until you add the correct BIOS files.
See Emulators for which core or app each system uses.
How do I add an emulator or system that is not in the list?
Open Settings > Game Settings > Game Systems and choose Add New System... at the bottom. You can point a new system at any RetroArch core or standalone emulator app, set its extensions, folders, and icon. The full walkthrough is on the Custom System page.
My games have no boxart
Run the scraper: Settings > Game Settings > Boxart Scraper, then Scrape All Systems. You can also scrape a single game from its Options menu with Scrape This Game. Art downloads in the background while you are idle. Full guide on the Boxart page.
How do I switch home themes?
Go to Settings > Theme Settings > Home Theme and pick GammaOS XMB, DSi Menu, or Minima. Applying restarts the home so the new look takes effect right away. See Themes for what each one looks like.
The screen is too dark or a shader broke the display
Hold Power + Select together. This disables the system display shader, which is the escape hatch when a shader (like the CRT Shader) makes the screen unreadable. Then adjust or turn off the shader in the GammaOS Toolbox.
For a screen that is simply dim, hold Select + Vol + to brighten it.
The home screen is frozen
Force a restart of the home:
- Hold Back for 10 seconds, or
- Hold the Guide / Mode button for 10 seconds.
Either one restarts a frozen or dead home screen.