Onion OS is the custom firmware that turns the Miyoo Mini Plus from "good handheld" into "great one." This guide covers what Onion OS is, the six benefits you'll feel within the first hour, and a step-by-step install. Updated for 2026 with current installation steps.
Don't own one yet? The Miyoo Mini Plus runs Onion OS better than any other handheld. Get it at LitNXT for $39.99 → (use code NY2026 for 12% off).
What is Onion OS?
Onion OS is an open-source custom firmware built by the community specifically for the Miyoo Mini and Miyoo Mini Plus. It replaces the stock OS on your microSD card — your device's internal firmware stays untouched, so it's completely reversible. Pull the SD card and you're back to stock.
It exists because the stock Miyoo OS, while functional, is missing nearly every modern feature retro gamers expect: save states, rewind, organized game libraries, box-art scraping, themes, and consistent emulator settings. Onion OS adds all of that and more.
Why use Onion OS on your Miyoo Mini Plus — 6 reasons
1. Better emulator performance
The first thing you'll notice is how much smoother everything feels. The firmware is tuned to reduce input lag and bump emulator performance across NES, SNES, Game Boy Advance, and PlayStation 1. PS1 in particular goes from "playable" on stock to "fluid" on Onion OS.
If you've ever had Castlevania: Symphony of the Night freeze or Pokémon Emerald crash mid-battle on stock, Onion OS is the fix.
2. Clean, organized UI
The stock OS surfaces every game in one flat menu. Onion OS sorts your library by console, lets you favorite titles, supports themes, and gives you a "recently played" view. Browsing 500+ ROMs becomes pleasant instead of a chore.
3. Real save states (and rewind)
Onion OS gives you multiple named save states per game, optional auto-save on exit, and rewind support in compatible emulators. This single feature changes how you play — you can experiment with tough boss fights without losing 40 minutes of progress.
4. Box art and metadata
Onion OS supports artwork scraping, so your library shows cover images, console logos, and release info next to each title. The handheld stops feeling like a file browser and starts feeling like a curated shelf.
5. Themes and deep customization
Pick from a growing community library of themes, boot animations, and system sounds. Hotkey behavior, emulator settings, list views — all configurable per system. If you enjoy tinkering, this is the firmware.
6. Active community + frequent updates
Onion OS is on GitHub with regular releases, a Discord community, and an extensive wiki. When you hit something weird, the answer is usually one search away. Stock firmware gets vendor updates roughly never.
How to install Onion OS on the Miyoo Mini Plus
Installation takes about 15 minutes. The process doesn't touch internal firmware — everything happens on the microSD card.
What you'll need
- A Miyoo Mini Plus (not the original Miyoo Mini — they use different builds)
- A microSD card, 32GB or larger recommended (64GB+ if you want a deep library with box art)
- A computer with a microSD card reader
- A stable internet connection
Step-by-step installation
- Back up first. If you've been using your Miyoo Mini Plus, copy any save files or ROMs off the SD card to your computer. Installation reformats the card.
- Download Onion OS. Go to the official Onion OS GitHub releases page and download the latest release ZIP. Make sure it's the Miyoo Mini Plus build (not the original Miyoo Mini).
- Format the microSD card. Use SD Card Formatter and format the card as FAT32. This avoids file-system compatibility issues. Don't use ExFAT or NTFS.
- Extract and copy. Unzip the Onion OS download and drag every file directly to the root of the SD card. Not into a folder — just at the top level.
- Eject safely, then insert the SD card into your Miyoo Mini Plus.
- Power on. The Miyoo Mini Plus detects the Onion files and runs first-boot setup automatically. This takes a few minutes.
- Follow the prompts for language, theme, and button mapping.
- Add your ROMs. Power off, put the SD card back in your computer, and drop ROMs into the correct folders under
Roms/— e.g.Roms/GB,Roms/SNES,Roms/GBA. Onion OS detects and sorts them on next boot.
That's it. You're running Onion OS.
If something doesn't boot, the Onion OS wiki and the r/MiyooMini subreddit are where to look first.
Want box art on every game?
Once Onion OS is installed, the next upgrade is automatic box art. We have a complete guide for that: How to Add Box Art to OnionOS / GarlicOS.
Other handhelds worth a look
Onion OS is Miyoo-specific, but if you're shopping around, these are the handhelds we recommend alongside the Mini Plus:
| Device | Why | Price | Buy |
|---|---|---|---|
| Miyoo Mini Plus | Best Onion OS device. The reference. | $39.99 | LitNXT → |
| Miyoo Mini V4 | Smaller form factor, same Onion OS support | $109.99 | LitNXT → |
| Miyoo Mini Flip | Clamshell design, Onion OS compatible | $39.99 | LitNXT → |
| Miyoo Flip V2 | Newer clamshell, Surwish OS variant | $39.99 | LitNXT → |
Browse our full Miyoo device guide to compare every model side-by-side.
Bottom line
If you own a Miyoo Mini Plus and you're still on stock firmware, you're using maybe 40% of what the device can do. Onion OS is free, takes 15 minutes to install, doesn't risk your hardware, and is reversible. There's almost no reason not to.
Need to grab a Miyoo Mini Plus first? Buy it at LitNXT for $39.99 → — use NY2026 at checkout for 12% off.
