Miyoo Mini (and Miyoo Mini Plus) Starter Guide

Last updated: 05NOV2023 (see Changelog for details)

This guide will show you everything you need to know about the Miyoo Mini and the Miyoo Mini Plus — where to buy one, the best tools to get it set up, accessories, and how to install custom operating systems like Onion and MiniUI.

Buy one here: AliExpress | Amazon (faster shipping) | KeepRetro | DroiX

Note that due to demand, availability has been an issue. The cheapest prices will be through the official Miyoo store on AliExpress, but you will need to check periodically to see when the device will be in stock. You can also try third-party vendors like KeepRetro or DroiX, or you can pay a premium price on Amazon to get it more quickly.

Table of Contents:

Recommended tools
Accessories and mods
Update to the April 2022 firmware (Miyoo Mini)
Update to the March 2023 firmware (Miyoo Mini Plus)
OnionOS installation
Add BIOS files
Add game files and images
Nintendo DS and Pico-8
Multiplayer (Miyoo Mini Plus)
Customize your themes
MinUI installation
MinUI fork installation
Custom boot logo

Changelog

Recommended tools

To install new firmware, I recommend starting from scratch with a new microSD card. You could use a 16GB card to save on costs and keep your game library trim, or you could fill it up with the works. Personally, I use a 32GB card in mine, with only a few PS1 and Sega CD games taking up the majority of the space. Here are the cards I recommend:

16GB cards: 
SanDisk Ultra  
SanDisk Industrial

32GB cards:
Samsung Pro Endurance
SanDisk Extreme

64GB cards:
Samsung Pro Endurance
SanDisk Extreme

128GB cards:
SanDisk Extreme
Samsung EVO Select
Samsung Pro Endurance
SanDisk Ultra

The Miyoo Mini/Plus will come with a cheap SD card reader, but I recommend a nicer one instead. This one from Anker has never done me wrong.

Accessories and mods

One of the great things about a popular device like the Miyoo Mini is that the community comes together to find all sorts of accessories and solutions to every little need. There are plenty of choices when it comes to custom buttons and stickers, 3D-printed grips, and more. The original Miyoo Mini is approximately the same size as a deck of playing cards, so playing card cases are great alternative carriers for this device.

Cases:
Maze (synthetic) leather case
Custom leather case
Hardshell case (use coupon RETROGAMECORPS10)
Snap-on screen protector case

Other accessories:
Buttons and stickers (Sakura)
Better Buttons (GetBetterButtons)
Magnetic charging dock
3D-printed grips

Update to the April 2022 firmware (Miyoo Mini)

In order to use the most recent versions of OnionOS, you must first update the Miyoo Mini base firmware to the April 2022 (or later) version. To check your firmware version, go to Setting > Device Info and verify the the “Version Number” is 202204190828 or “20221216XXXX” — if so, you are good to go to the next section. If it is something earlier (i.e. it starts with 202201… instead) then follow the firmware update instructions below.

• Save any important game files or your BIOS folder to your computer just in case.
• Go to the Miyoo website and download the latest image update, then unzip the file.
• In the unzipped folder, go to “The firmware” > miyoo283_fw.img and drag that file into the root of your Miyoo Mini SD card
• Go to “TF card” folder and drag the three subfolders (Emu, miyoo, and RetroArch) into the root of your card, and replace any existing files when prompted (this part is optional).
• Eject the SD card from your computer and plug it into the Miyoo Mini
• Plug the Mini into a wall charger, and be sure to use use a low-wattage wall plug. For best results, use a USB-A to USB-C cable, and a “smart” plug that can adjust wattage, or one of those cheap 5V/1A plugs that used to come with cell phones.
• The Miyoo Mini will automatically power on and run the update. Don’t touch the device at all!
• The device will restart and will then display a battery image and the charging screen. At this point you are done. Unplug the device from the cable and remove the SD card.
• Plug the SD card into your computer and delete the miyoo283_fw.img file before doing anything else.

Here is a fancy infographic (credit: PIXELSHIFT and TNGLIKER) that walks you through the process. Their process is a bit different, in that they move the “TF card” files to the SD card after the upgrade; either method works fine.

If you are having issues upgrading your device, or it gets caught in a loading screen while flashing the new firmware, follow the instructions provided in this Reddit comment.

Update to the March 2023 firmware (Miyoo Mini Plus)

The Miyoo Mini Plus will need to be updated to the 20230326XXXX (or later) firmware to take advantage of new developments for OnionOS. The video below will walk you through the process, but it’s as simple as downloading this firmware file and placing it in the root directory of your microSD card. From there, plug a 5W USB-A to USB-C cable into the device while it is off, and it will power on and update.

OnionOS installation

Here are the installation instructions for Onion. For a full list of features, stop by their Features page. If you run into any issues, be sure to check out Onion’s comprehensive wiki page.

• Format your microSD card to FAT32 file system.
  • If using Windows, use the guiformat tool to format the card to FAT32. You can name it whatever you want.
  • If you have a Mac, “Erase” the disk using the Mac’s built-in Disk Utility app, with the format MS-DOS (FAT), name it whatever you want.
• Head over to the Onion GitHub Releases page and grab the latest release (it will be a zip file).
• Unzip the file, and place all of the contents into your SD card.
• Eject the SD card and place it in your Miyoo Mini. Start up the device and it will run the installer.

To update from a previous release of Onion, check out the Onion upgrade instructions from their wiki page.

Credit for Onion goes to their wonderful ragtag team of community contributors.

Add BIOS files

Once you have run the Onion Installer, you can now shut down the device, eject the microSD card, and add your files to it.

In the BIOS folder, add your BIOS file collection. You can simply copy/paste the files from your stock SD card, or add your own. On the stock SD card, you can find the BIOS files under RetroArch > .retroarch > System

You will need to be able to see hidden files in Windows or your Mac to see the .retroarch folder. Here is how to do that:

• Windows 10: Open File Explorer from the taskbar. Select View > Options > Change folder and search options. Select the View tab and, in Advanced settings, select Show hidden files, folders, and drives and OK.
• MacOS: Press CMD + SHIFT + . (period) to show/hide hidden files.

To see a recommended list of BIOS files to add, head over to the Onion wiki page to see their list of emulators and recommended BIOS files for each system. For most systems, BIOS are not required, but can enhance the playing experience (like adding the original boot logo when starting up a game). For systems like PS1, Sega CD, and TurboGrafx-CD, BIOS are a necessary component.

Add game files and images

In the Roms folder, add your game files into the corresponding subfolder. Some of the folders are named after their Japanese counterpart, like “FC” (Famicom) for NES, “MD” (Mega Drive”) for Sega Genesis, or “PCE” (PC-Engine) for TurboGrafx-16. For a full listing of each folder and the accepted file extensions, check out the Onion wiki page. You can also run a limited number of ports and third-party apps on the device, too.

When adding game files for systems that use the same RetroArch core file, you can create subfolders. For example, You could make Sega CD and Sega 32x subfolders inside of your Sega Genesis to clean up your front menu and streamline the navigation experience.

If you would like to add boxart to your games, here is more information. You can also check out the Nintendo DS video below to see how to scrape boxart online on the Miyoo Mini Plus.

For a list of hotkeys in Onion, check out this page. For more in-depth features and issues, check out their FAQ page.

Nintendo DS and Pico-8

Recent updates from the community now allow for Nintendo DS emulation and the ability to play Pico-8 games (and its trademark Splore menu) natively. See the video above for a demonstration and walkthrough of the experience. Both apps will work fine on the Miyoo Mini and Miyoo Mini Plus, but for the online functionality of Pico-8, you will need a Miyoo Mini Plus connected to the Internet. Note that these apps require you to be running the latest version of OnionOS.

Nintendo DS: Head over to this GitHub page and download the latest version of DraStic. Using 7zip, open the 7z file and you will find a folder named “drastic” within. Move that folder over to the “Emu” folder on your OnionOS microSD card. Now, within the “Roms” folder on your SD card, make a folder named “NDS” and put your Nintendo DS (.nds) files inside. You should now see DraStic as a system option within your Games menu on the device. Here are some common hotkeys for DraStic:

R2	Swap screen
L2	Change Keypad mode / Stylus mode
SELECT + R1	Fast forward
SELECT + R2	Quick save state
SELECT + L2	Quick load state
SELECT + L1	Exit DraStic emulator
SELECT + START	Enter the customized menu

Pico-8 (Native): To play Pico-8 natively, you will need the data files from the commercial license (Raspberry Pi version), which you can purchase here. After that, go to this Reddit post to download the app file at the bottom of the post. Open the app file, then the tar file within it, until you find a folder named “pico” — place this folder in the “App” folder on your OnionOS microSD card. Next, open your Raspberry Pi Pico-8 file and find two files:

• pico8_dyn
• pico8.dat

Copy these files over onto the App/pico/bin folder on your OnionOS microSD card. Put the card back into your device and you will now find Pico-8 within the Apps menu of OnionOS.

Note that you will need to be connected to WiFi (i.e. on the Miyoo Mini Plus) in order to take advantage of the Splore browser menu. If you would like, you can manually add games (“carts”). To do so, go to the Pico-8 website and find some games you want to play (you can play them directly in your browser to test them first). Once you find a game you like, in the game’s window there will be a little “cart” icon on the bottom-left. Right-click on that and select “Save As”, the file will be saved as a .png file. That is a Pico-8 cart! On your OnionOS microSD card, make a folder named “PICO” inside of the “Roms” folder, and add your carts there. Now, when you open up the Pico-8/Splore app, you will find them under the “Local” menu.

If you are looking for Pico-8 games to try, here are some great lists:

• Pico-8 recommendations thread on Reddit
• Pico-View is a monthly zine with lots of reviews and recommendations
• PicoShorts is a review series of Pico-8 games

Multiplayer (Miyoo Mini Plus)

The Miyoo Mini Plus has built-in WiFi, making it capable of netplay between multiple Miyoo Mini Plus devices. I’ve made two videos on the subject: first, the video on the left will show you how to set up RetroArch netplay for either local or over-the-internet multiplayer, and the video on the left will show you how to set up an ad-hoc network play session, and also how to trade and battle Pokemon for the Game Boy and Game Boy Color versions of the games.

Note that in the second video I mentioned the Pokemon saves will work across emulator cores, but it appears that if you want to use an older save file, it will need to be placed in the following folder on your SD card: Saves > CurrentProfile > saves > TGB Dual. The save file should be in .srm format. If you are unsure where to find your previous saves on the device, they are likely found in Saves > CurrentProfile > saves > Gambatte.

Customize your themes

The Onion apps section has the ability to install your own themes, and you can also grab more from this massive themes repository. Moreover, you can adjust the themes to your liking, or create your own.

You can also adjust the music in the themes; for example, you could download this lo-res version of the Retro Game Corps theme song and add it to your theme of choice. In a fun twist, this theme was written by Jim Gray, one of the first Onion developers. Thanks to HyperPragmatist for editing the song down to work as a Miyoo Mini theme! To add your own track, rename the file to “bgm.mp3” and place it in the Themes > [name of theme] > sound folder on your SD card). Note that the tracks need to be 96kbps, 48khz, mono, and under 2 minutes to work as a Miyoo Mini theme.

MinUI installation

MiniUI is a lightweight launcher that is focused on simplicity, and works on both the Miyoo Mini and Miyoo Mini Plus. As expected, the installation of MiniUI is simple. Note that the Miyoo Mini firmware upgrade is not required for MiniUI.

• Head over to the MiniUI GitHub page and download the latest release
• Inside the release will be a readme file, simply follow those instructions!
• If you would like to add the official “extra” systems, download the extras zip from the same releases page and follow the instructions inside the provided readme file
• If you would like to add community-driven “extra” pak systems, check out Tiduscrying’s repo.

Note that in my initial MiniUI video, I mentioned that some SNES games don’t play at full speed. One way to improve performance is to keep the games at Integer Scaling (“Native” in the options menu) which will improve performance. For example, Final Fantasy III (SNES) will play at full speed without frameskip when at Native resolution.

To update MiniUI, download the latest release (base version), unzip the file, and move the miyoo folder into your SD card. It will take care of the rest upon your next bootup.

Credit for MiniUI goes to the always-prolific Shaun Inman.

MinUI fork installation

The original MinUI developer did not initially provide official support to the Miyoo Mini Plus, and as a result a fork of MinUI was created:

DotUI is a port of MinUI that is compatible with the Miyoo Mini Plus, with no additional features other than some light branding changes. The installation process is the same as for MinUI above, just be sure to grab the installation file from this link instead.

That said, as of September 2023, MinUI has been updated to include official support for the Miyoo Mini Plus, so you now have plenty of options.

Custom boot logo

If you would like to use (or create) a custom boot logo for your Miyoo Mini, you can follow the instructions in the video above. This can be used with any firmware or operating system. Here are all the pertinent links that you’ll need to get set up:

LogoTweak app
Retro Game Corps boot logos (right-click and select “Save As…”)
Additional boot logos from artist JDewitz (right-click and select “Save As…”)
Additional boot logos from PaynefullyCreated (right-click and select “Save As…”)

If you happen to brick your device in the process (I haven’t heard of a single instance with any firmware except for those running 20221216XXXX, but it’s still theoretically possible on the older firmwares), here are instructions on how to recover your device. Here is another set of instructions to recover the device.

Note that the disappearing boot logo images in MiniUI (as shown in the video above) have now been fixed by the LogoTweak developer, so it will work great in both OnionOS or MiniUI.

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Changelog

05NOV2023
– added Nintendo DS and Pico-8 section

28SEP2023
– updated links to new Onion wiki page
– updated links to new MinUI page

21AUG2023
– added Multiplayer section
– added MinUI fork (MMP) section

11APR2023
– added new video link and Miyoo Mini Plus firmware update instructions

07JAN2023
– updated logo tweak section to warn users about potentially bricking their device if it is running 20221216XXXX firmware

01JAN2023
– updated warning to coincide with OnionOS v4.0.4 release which fixes the 20221216XXXX firmware issue

31DEC2022
– added warning about “20221216XXXX” firmwares

28SEP2022
– added Onion v4 installation guide video
– streamlined the accessories section

26SEP2022
– updated Onion install instructions
– separated the firmware update section
– added MiniUI update instructions

15AUG2022
– added custom theme music and custom boot logo instructions

26JUL2022
– updated links to OnionOS repo and FAQ fork

19JUN2022
– added additional complementary videos

15MAY2022
– published guide