Last updated: 15AUG2022 (see Changelog for details)
There is a new version of the Miyoo Mini available, and so in this video we’ll take a deep-dive review of the differences between the v1 and v2 versions of this tiny little device. Additionally, let’s set up new custom firmware using the latest versions of OnionOS and MiniUI.
If you are looking for the v1 Miyoo Mini Onion guide, you can find it here. Note that the v1 guide is now outdated.
Credit for Onion goes to their wonderful ragtag team of community contributors. They do not have a direct donation set up for the project, but if you are feeling generous, they requested you make a donation with the Mutual Aid Disaster Relief fund in their honor. Credit for MiniUI goes to the always-prolific Shaun Inman.
Table of Contents: Recommended tools OnionOS installation Add BIOS files Add game files and images Customize your theme music MiniUI installation Custom boot logo Changelog
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 an SD card reader, but I recommend a nicer one instead. This one from Anker has never done me wrong.
The Miyoo Mini is approximately the same size as a deck of playing card, so playing card cases are great alternative carriers for this device. You could try out the (synthetic) leather cases found in the video below, or even go super cheap with some $3 plastic cases.
Also in the video above I discuss some of the color options available, as well as how to fix light bleed on the transparent models if that’s something you’re interested in trying.
In order to use the most recent version of OnionOS, you must first update the Miyoo Mini base firmware to the April 2022 version.
- 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.
Now let’s actually install Onion.
- 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 you should have a single folder, and inside will be a subfolder named “.tmp_update”. Drag this folder into your freshly-formatted FAT32 microSD card. If you don’t see the folder, follow the instructions in the next section about enabling hidden files.
- Eject the SD card and place it in your Miyoo Mini. Start up the device and it will run the installer.
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. For best results, use the psxonpsp660.bin BIOS file for PS1.
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.
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.
Customize your theme music
The Onion apps section has the ability to install your own themes. Moreover, you can adjust the themes to your liking. 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 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.
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. Here are all the pertinent links that you’ll need to get set up:
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, but it’s still theoretically possible), 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.
– added custom theme music and custom boot logo instructions
– updated links to OnionOS repo and FAQ fork
– added additional complementary videos
– published guide