How to Fix Games Not Launching (Crashing Back to Menu) on the Miyoo Mini Plus

Causes

• Missing, renamed, or corrupt BIOS files from the bundled card — OnionOS runs games through RetroArch cores, and several systems need a specific BIOS file with an exact filename and location (for example the PlayStation needs scph1001.bin in the BIOS folder, and Game Boy Advance needs gba_bios.bin). The cheap card shipped with the Miyoo Mini Plus often has these files missing, renamed, or half-written, so the core fails instantly and the device bounces back to the game list.
• Corrupted or truncated ROM files — a ROM downloaded over a dropped connection, or a card pulled out mid-copy, leaves an incomplete file that the core cannot parse. The Miyoo Mini Plus shows Loading for a split second, the screen goes black, then returns to the menu with no error.
• Incomplete OnionOS or core installation — copying Onion files over an old install, skipping the on-device installer, or letting a low battery interrupt setup leaves missing cores and config folders. When RetroArch itself will not even initialize, every game "crashes back to menu" even if the ROMs and BIOS are fine.
• Wrong ROM folder structure or a stale game list — every system has a dedicated folder under Roms, and OnionOS builds the visible game list from it. ROMs dropped in the wrong folder, or a game list that was never refreshed after adding files, point to paths that no longer exist and fail to launch.
• The failing bundled microSD card itself — the stock card degrades under sustained read load. Games can appear in the list (light reads) but fail to load (heavy reads during core boot), a failure mode that worsens until the card fails entirely.

How to Fix

1. Verify every BIOS file is present and correctly named — unplug the SD card and open the BIOS folder on a computer. Confirm the exact file each core needs: for PlayStation use scph1001.bin, for Game Boy Advance use gba_bios.bin, and for Neo Geo use the neogeo.zip archive. Filenames are case-sensitive and must match precisely; a wrong name is the same as a missing file.
2. Refresh the game list — back in OnionOS, press the Select button in the game list (or launch Game Switcher → Refresh ROMs). If you recently added or moved files, this rebuilds the visible list so entries point to the folders that actually hold your ROMs.
3. Do a clean OnionOS install — back up the Saves and BIOS folders, then format the card to FAT32 with a 32 KB allocation size (not quick format, via Rufus on Windows or the FAT32 option in Disk Utility on macOS). Extract the latest OnionOS release to the card root and let the installer run on first boot. Skip the previously written card entirely rather than copying an old retroarch folder over the new one.
4. Re-install or replace the RetroArch core package — if RetroArch itself won't open, open Apps → Package Manager in OnionOS and reinstall the RetroArch core package, then reboot. A corrupted retroarch folder is one of the most common reasons every game bounces back to the menu.
5. Re-copy and verify your ROMs — copy ROMs with a known-good USB card reader and safely eject before unplugging. Test one known-good ROM on a PC emulator or another device; if a file is bad, replace it rather than copying the same broken file back.
6. Replace the bundled card with a quality card — move everything to a brand-name A1 or A2 microSD card (SanDisk, Samsung, or Kingston). The bundled card is the single most common root cause of intermittent game-loading failures on the Miyoo Mini Plus, and a good card resolves them for most owners.
7. Confirm the firmware version and test the default core — make sure the OnionOS and stock firmware versions are current, then launch a game with a light core (GB, NES) before trying heavy systems like PS1/N64. If a specific heavy core still bounces, the problem is that core/BIOS combo, not the device.