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  5. Miyoo Mini user guide – OnionOS 3

Miyoo Mini user guide – OnionOS 3

OnionOS version

This guide covers OnionOS version 3. If your Miyoo Mini is running OnionOS 4, please see our new guide.

K-TEC enhancements

We have used our expert knowledge to tune the configuration of your Miyoo handheld. If you discover other tips or configurations that enhance your experience, please use the contact form to let us know. Here’s a list of the changes we’ve made.

microSD cards

The microSD cards that Miyoo usually supplies with its handhelds are unbranded and we are not satisfied with their reliability. Therefore, we ship these devices with brand-name microSD cards.

We are so confident about the quality of these cards that we provide a lifetime guarantee.

It’s important to make a backup

Even with the lifetime guarantee we give our microSD cards, it is still recommended that you backup your card(s) as soon as you receive your device. See How to backup your retro handheld’s microSD card(s)


We have replaced the stock firmware with the OnionOS custom firmware. In our testing, OnionOS provided excellent balance between ease of use and performance. We have further refined the configuration of the firmware with settings specific to the Miyoo Mini.


Powering on the device

Hold the POWER button for a few seconds.

Turning off the device

Hold the POWER button for a few seconds. Your device will now power down safely. If a game is open, your Miyoo Mini will automatically create a save state before shutting down1. When you next start that game, it will continue from that save state.

Hard shutdown

If the device crashes, and the above method doesn’t work, a hard shutdown can be performed by pressing START + SELECT + R2 + L2.

This method should only be used as a last resort as it risks data corruption.


Your Miyoo device is a handheld computer and, as such, should be powered down in a safe manner. Otherwise, there is a risk of data corruption.


Your Miyoo handheld can be put into sleep mode by pressing FUNCTION + POWER2. If you press the power button again, the device will quickly return to the state it was in before entering sleep mode.


This is only a light sleep mode and still drains the battery. We do not recommend using it for long periods of time.

Navigate between systems

Most of the systems supported by this device can be found in the Consoles section. The Expert section contains systems that are more experimental. The games you play from this section may be a little more prone to crash. We’ve included them because we feel that what they add to your gaming experience is worth it.

Navigate through a game list

To speed up the process of scrolling through a game list, use L1 and R1 to move a page at a time.

You may also find it convenient to use the Recent section to find your most recently played games.

Quitting a game

Usually pressing the FUNCTION2 button is enough on its own. With some games, you have to press FUNCTION + SELECT2 to bring up the RetroArch menu, then press B, then scroll down to Quit RetroArch.

If you power down the device with a game still running, it will automatically create a save state while it switches off1.



The FUNCTION button is the small, circular button in the middle of the device. The OnionOS documentation calls this the MENU button. The following hotkeys work when pressed together with the FUNCTION button.

Light sleepPOWER
Create save-stateR2
Load previous save-stateL2
Fast-forware (toggle)R1
RetroArch menuSELECT

Additional hotkeys, not used in combination with the FUNCTION button.

Brightness upSELECT + R2
Brightness downSELECT + L2

See https://github.com/Sichroteph/Onion#shortcuts for more.


You can add a game to the Favorites section by pressing the FUNCTION2 button and selecting Add as favorite.

On-screen keyboard (for home computer systems)

Home computers – such as the Amiga, Commodore 64, Amstrad CPC, and ZX Spectrum – included a keyboard. Games for these systems often require keyboard input actually to start the game-play or to choose joystick mode.

To bring up the on-screen keyboard, for most systems, press SELECT. For the Amstrad CPC, press R2.

If the system seems to be waiting for you to do something, try bringing up the on-screen keyboard and pressing SPACE or RETURN/ENTER.

If a game asks for an input method, we recommend that you choose Joystick or, in the case of the ZX Spectrum, Kempston.

Famicom Disk System (FDS)

Famicom Disk System games often require you to change discs. Use the following input sequence to do so:

  1. R2 to eject the current disc
  2. L2to select side B
  3. R2 to load side B

Fast-Forward and Rewind

Your Miyoo Mini, with OnionOS, allows you to Fast-Forward or Rewind games.

To Fast-Forward, press FUNCTION + R12. This toggles on Fast-Forward mode and can breeze past sections of games that seem to move too slowly. To return to normal speed, press FUNCTION + R12 again.

Sometimes you may wish to Rewind the action in a game to undo a quick fail. Press and hold FUNCTION + L12.

Not enabled on all consoles

Fast-Forward and Rewind are enabled on most systems, but there are exceptions; such as the PlayStation, Amiga, CPS3, NeoGeo-CD, Virtual Boy, and ZX Spectrum, where there would be an adverse effect on performance.

Autosave & save-states

On most systems, when quitting a game, it will automatically create a save-state1. When next launching the game it will start the action at the same point.

Also, you can create a save-state at any moment of your choosing – press FUNCTION + R22. To re-load that save-state, press FUNCTION + L22. This can be helpful when dealing with a tricky boss.


The Ports section contains games that run natively on your Miyoo Mini, without the use of an emulator. This means that games can run more smoothly and with better performance. It may be interesting to compare the Doom port with the same game on emulated systems.

Pico-8 and Tic-80

Pico-8 and Tic-80 are Fantasy Consoles. These aim to create the experience of retro-gaming without the need to emulate a real hardware console.

A fantasy console is like a regular console, but without the inconvenience of actual hardware. PICO-8 has everything else that makes a console a console: machine specifications and display format, development tools, design culture, distribution platform, community and playership. It is similar to a retro game emulator, but for a machine that never existed.

zep, “What is a Fantasy Console?”, https://www.lexaloffle.com/pico-8.php?page=faq

It’s remarkable what some game developers can do within the constraints of these fantasy consoles, and their games are worth checking out. A great example is Celeste, originally made for Pico-8, and is included with your device.

Setting the clock for Pokemon games

The Miyoo Mini does not feature a Real-Time Clock (RTC). It compensates for this by adding 4 hours to the time upon every reboot.

For games that may require finer control over the stored time, such as the Pokemon games, you can use the Set Clock app. Set the time and date to whatever you wish. Again, 4 hours will be added when you next start your device.

Switching themes

Your Miyoo Mini comes with a range of themes. You can choose your preferred theme by running App -> Theme Switcher.

If your chosen theme features background music, its volume level can be configured in the Settings menu.

Show the Retroarch menu

Press the FUNCTION + SELECT2 buttons when playing a game that uses a RetroArch core. You can adjust many settings here, but OnionOS has done a good job of optimizing these for you.

You can also see the RetroArch menu by running the RetroArch item in the App section.

Onion Launcher mode (this is clever)

Onion Launcher mode will boot straight into the last game you were playing, starting at the point where you last quit the game1. It also offers stream-lined navigation between your ten most recent games.

Enable Onion Launcher mode

In the App section, run the Onion Launcher item. This will enable Onion Launcher mode on the device.

Now power off your Miyoo Mini. When you power on, it will automatically start the last game you were playing at the most recent save-state.

If you power down the device while a game is running, it will automatically create a save state1.

Navigating between recent games

If you quit the game (using the FUNCTION2 button) it will exit into Onion Launcher mode. If you press Left and Right on the D-pad, you will navigate between your ten most recent games. Press the FUNCTION2 button to launch the game with its most recent save-state.

Disable Onion Launcher mode

  1. Quit the game using the FUNCTION2 button to get into the Onion Launcher mode
  2. press START (this takes you to the usual OnionOS menu)
  3. go to the App section and run the Onion Launcher item again.

Guest mode

If want to let someone else use your Miyoo Mini, but you’re concerned they might mess up your save points or configuration, you can put the device in Guest mode.

Run App -> Guest mode and switch off the device. When you switch the device back on, your guest can play games without overwriting your save states.

To return the device to normal, just run App -> Guest mode again.


This is the Operating System that runs on your Miyoo retro handheld device. It provides numerous improvements to the stock firmware.
Retroarch provides most of the cores/emulators that run the provided games. The Retroarch menu is used to configure its cores.
A Core is an emulator that has been adapted to work with Retroarch.
An emulator allows your device to pretend that it’s a different device. For instance, the PCSX4ALL emulator enables your Anbernic retro handheld to pretend that it’s a PlayStation and run games designed for the PS1.
  1. A few systems do not support this feature, including ARCADE and Pico-8 [] [] [] [] []
  2. The FUNCTION button is the small, circular button [] [] [] [] [] [] [] [] [] [] [] [] []
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