Miyoo Mini Starter Guide

Last updated: 07JAN2023 (see Changelog for details)

This guide will show you everything you need to know about the Miyoo Mini — 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

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 KeepRetro who will take your order and ship it when it is available, or you can pay a premium price on Amazon to get it more quickly. Here is a video with tips on how to buy a Miyoo Mini.

Table of Contents:

Recommended tools
Accessories and mods
Update to the April 2022 firmware
OnionOS installation
Add BIOS files
Add game files and images
Customize your themes
MiniUI installation
Custom boot logo


Recommended tools

128GB SanDisk Ultra and Samsung EVO Select microSD cards

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 (which will also result in faster navigation), 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 v2 comes 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 Miyoo Mini is approximately the same size as a deck of playing cards, so playing card cases are great alternative carriers for this device.

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

Other accessories:
Buttons and stickers
Magnetic charging dock
3D-printed grips

Update to the April 2022 firmware

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.

PSA: new Miyoo Mini devices are showing up with “20221216XXXX” firmware on them and they are only compatible with OnionOS v4.0.4 and later. Be sure to use the latest OnionOS release.

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.

image courtesy of Onion team

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

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.

MiniUI installation

MiniUI is a lightweight launcher that is focused on simplicity. 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.

Custom boot logo

Note that as this time, if you are running the 20221216XXXX firmware on this Miyoo Mini, this process will brick your device. This is only recommended for devices running firmware older than 20221216XXXX.

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.


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

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

– added warning about “20221216XXXX” firmwares

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

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

– added custom theme music and custom boot logo instructions

– updated links to OnionOS repo and FAQ fork

– added additional complementary videos

– published guide

24 thoughts on “Miyoo Mini Starter Guide

  1. I just ordered a V1 and I was wondering if this guide is applicable to that or just the V2? I want to make sure to get Onion on there and want to get everything done right!


    1. Yes, this will also work with the V1 model, as long as you’ve updated the base firmware to the April 19 release.


      1. Appreciate it! I’m so spoiled with US shipping. The wait is killer for AliExpress.


  2. My V2 justed arrived, but without any sd-card. I found a download-link to the image, but it’s not recognized by the miyoo mini. It says “unmounted”. I flashed the zip-file as an image to the sd-card. Any ideas how I can get my device to work?


  3. Thanks for making this update video, I kinda had to put my Mini on the back burner for a little bit because I wasn’t sure how to get Onion installed. Works great now though!


  4. Now the firmware upgrade comes with two TF Card folders and it is not clear which one should go on the sd card.


  5. Hi Russ,
    great video, made me instantly order a V2 version, although I also have the V1. It arrived (finally!) today and I tried to copy over my save files from V1 to V2. So here’s what I did:
    (Note: I have Onion OS installed on both devices, also the same emulators)
    – Copied the roms to their exact folders from device 1 to device 2, maintaining their file names
    – Copied the \states and the \saves folders into their respective RetroArch folders
    – Started up a game that I had previously save files for
    But nothing happens, the game starts from the beginning, as if there never was a save before. Manually loading a save file through RetroArch doesn’t work either.
    So, HELP please! How can I get my save files to work on the V2 device? Thanks!


  6. Hey Russ,

    I installed the OnionOS v3.11.2 on my Miyoo Mini v2. The problem is that on the Miyoo Mini I can see all the hidden files when navigating through the interface. For example in NES section I can see the ._* versions of the games I added to the FT card so that the game count shows the double of actual games. And those hidden files with the names of actual games won’t even open.

    I would appreciate your advice,

    Thank you in advance


  7. Onion OS doesnt load some roms after following this guide.
    GBA, FC, and SFC roms bring up a loading text then returns back to the Onion OS rom list. But if I Apps>RetroArch>Load Content>Navigate to ROM folder>Run rom with any core it works. I have verified the naming/path/capitalization is correct.

    My GB and PS Roms work from the OnionOS Menu

    I installed Onion OS on a fresh SD card and just copied the roms from the Stock SD over.


    1. I had better luck running PS1 games in BIN/CUE format. Probably, ISO format, too. PBP originally is the format that PSP runs for when emulating PS1 titles natively.


  8. Today I got my Miyoo Mini V2 (Firmware is already 20220419 ) and wanted to install the newest onion firmware. I formated a new sandisk 32gb microsd card and copied the “.tmp_update file” to the root of the sdcard and put it back to the miyoo mini. After powering on the device the onion installation screen appeared but stuck in showing “Installing cores” for hours. Nothing more happened 😦
    Afters 2 hours I disconnected the battery and tried to boot with the old microsd with original firmware.
    Luckily this worked 😉
    I tried with another sdcard, but same problem 😦
    Any idea for help?
    How long is the normal process when installing onion, How long do I have to wait till process is ready? Minutes or hours?


  9. Hey!
    New update of MINIUI was released: MiniUI-20220910
    I’ve got a question…what does this mean? extras: renamed SFC.pak to SUPA.pak (for use with collated folders)


  10. I’ve just updated my miyoo with onion and suddenly the roms and emulators are not visible when I boot the device? I just get an empty games page and nothing changes after I refresh the roms list. Has this been seen?


  11. hi, im new to do this. i just got a miyoo mini v2 but without SD card from a third party. if i can get my own SD card will it be possible to download games onto my miyoo?
    can anybody help me out with this?

    thanks in advance! – Nick


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