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What to expect:

OnionOS is possibly the best retro gaming operating system on the scene. It comes preloaded on all Miyoo Mini Plus’ bought from GoGameGeek now. So today I am going to check out the OnionOS build on a Miyoo Mini Plus they sent me, along with a quick refresher review on why this is THE retro gaming device for 8 and 16 bit systems.

So I have mentioned GoGameGeek, they explained to me that you can actually buy these preloaded SD cards with their custom version of OnionOS. This is a great way to get set up easily without too much drama.

OnionOS key features:

  • Onion have an excellent info section on the OS here
  • We will just go through the highlights and things that you may find difficult to navigate
  • GoGameGeek boot logo
  • GoGameGeek have curated a really nice roms library
  • They appear to have added shaders and filters for you too
  • GameSwitcher: press the menu button once at any point to see screenshots of your recent games
  • Package manager: essentially your App Store where you can manage emulators and apps
  • Tweaks: allows you to fully customize the system. I like being able to set where the system starts up to
  • Themes: excellent selection
  • App manager: download the OTA updater, they also have a music player which I know a lot of people like
  • Boxart scraping supported in the latest release
  • Retroachievements
  • Native Pico8
  • Recently Nintendo DS support was added
  • GLO – per games core adjustments

How to add Pico8 to Onion V4.3

You’ll need to provide 2 files for the RASPBERRY PI version of pico-8:

  • pico8_dyn
  • pico8.dat

Download these files here:

  • Download the .tar.gz file and unzip it with something like 7zip:
  • Drag the app folder from the releases page into SDCARD/App/ (so it becomes /mnt/SDCARD/App/pico)
  • Now purchase Pico8 here:
  • Download the Rasberry pi version and extract the zip folder
  • Now go back to your SD card and add a “bin” folder to the app/pico/ folder if it doesn’t already exist
  • Now  drag the pico8_dyn and pico8.dat files from the Pico8 folder you just bought to the app/pico/bin/ folder
  • Insert the SD card back into your device and start it up
  • Navigate to apps and open Pico8 Wrapper
  • Press MENU + SELECT to exit Pico8
  • Also make sure you’re connected to the internet

Unique to GoGameGeek:

  • They tell me the overlays and tweaks are specific to this version of the OS
  • For me the key difference is the ROMSET, although it’s fairly sketchy, their romset is really nice though. They’ve curated A LOT of games across many systems with seemingly no bias so you can explore devices and consoles that you never saw in real life like ATARI Lynx or NeoGeo Pocket
  • Also it ships with a SanDisk card which is excellent quality


  • General navigation: quick switch, single press to game switcher, long press to menu, X to search, screenshots in the gameswitcher, opens where you left off after shut down. This workflow is what makes OnionOS so special

Shortcuts I like:

  • Volume indicator throughout
  • X in menu system opens search
  • Menu + volume = brightness setting
  • Double press menu button to quick switch to your previous game (multi tasking!)
  • MENU + L / R = rewind / fast forward
  • MENU + L2 / R2 = Load State / Save State
  • L2 + R2 = Change Colour Palette in GB games (particularly nice because I really don’t like the normal setup where simply pressing L2 or R2 changes the palette so you end up changing the colour while saving)

Better overlays:

  • Gameboy:
    • Open a Gameboy game
    • Menu + SELECT > On-screen Overlay > Overlay Preset > GB-GBC > Frame > DMG-480p-mini.cfg
    • Settings > Video > Scaling > Integer Scaling ON / Keep Aspect Ration ON
    • Quick Menu > Overrides > save content directory overrides
  • Gameboy Color:
    • Open a GBC game
    • Menu + SELECT > On-screen Overlay > Overlay Preset > GB-GBC > Frame-Grid > GBC-480p-final.cfg
    • Settings > Video > Scaling > Integer Scaling ON / Keep Aspect Ration ON
    • Quick Menu > Overrides > save content directory overrides
  • Gameboy Advance:
    • Open a GBA game
    • Menu + SELECT > On-screen Overlay > Overlay Preset > GBA > GBA-480p-scan.cfg
    • Quick Menu > Overrides > save content directory overrides
  • Gamegear:
    • Open a Gamegear game
    • Menu + SELECT > On-screen Overlay > Overlay Preset > GG > Frame > Gamegear_new.cfg
    • Settings > Video > Scaling > Integer scaling ON / Keep aspect ratio ON
    • Quick Menu > Overrides > save content directory overrides


  • Video player for the true retrophiles!
  • Music player… I do not have a sinle mp3…
  • Themes – here’s a cool theme made by TechDweeb! And so many more in v4.3

Things I like about the MM+:

  • Screen
  • Navigation
  • Themes
  • Dpad – one of the best modern retro dpads
  • Design is so retro

Things I don’t like about the MM+:

  • I can’t find a way to disable the LED light which is an absolute pain on the clear shell – the best I can do is undervolt it to reduce the brightness: Tweaks > Advanced > LCD undervolt BUT this reduces the overall screen brightness (which saves on battery life)
  • Ergonomics: here’s where my previous video had a critical flaw – something like the Anbernic RG35XX is far more comfortable to hold.
  • No HDMI output – if you’re looking for something to consolise this is NOT for you
  • I tried an OTA update and it didn’t work. Fortunately their update guide is excellent – also the GoGameGeek tweaks were not lost when I updated

Major competing devices:

  • RG35XX H Plus more power but OS isn’t great, but it has HDMI out
  • RGB30 more expensive but more powerful and amazing screen for older systems and to play Pico8