Installing Onion OS
In order to play music, we’ll be using the Gmu app. This app is available on Onion OS so we will need to install it onto your Miyoo Mini or Miyoo Mini Plus.
The easiest way to do this is to use the Onion Desk Tools found here: https://github.com/schmurtzm/Onion-Desktop-Tools/blob/main/README.md
Click on the “Download Onion Desktop tools” link, extract the files using a program like 7-Zip (https://www.7-zip.org/), and start the _Onion Desktop Tools - Launcher.bat file.
Windows will ask for permission, click “Yes” to proceed and the user interface will pop up.
Plug your microSD card into your computer using a USB adapter.
Select the Format SD card and install Onion option and make sure to select your microSD card in the following prompt.
Formatting means all data will be erased and very hard to recover. If you want to keep any data on the microSD card, make sure to back it up somewhere!
After the process is done you can safely eject the microSD card using the prompt in Windows and then insert the card back into your Miyoo Mini. Once you turn it on, the installation process should finish.
In the future, if you need to update Onion OS, you can choose the Install/Upgrade/Reinstall Onion (without formatting SD card) option.
Different File Transferring Methods
If you want to wirelessly transfer files to your Miyoo Mini Plus (regular Miyoo Mini does not have WiFi), you can use the HTTP file sync.
Before you enable this, I would recommend not doing this on a public WiFi network since anyone can access your device. Only do it at home.
On your Miyoo Mini Plus, go to Settings -> Wifi, and turn on WiFi and connect to your home network.
Back out and go to Apps -> Tweaks -> Network and enable the HTTP: Web-based file sync….
Copy the IP address shown on the top of this menu.
It will most likely start with 192.168.0. and end with a number.
Go to your computer and type in the IP address and hit enter. It will bring up a simple interface to manage files with. You can drag and drop music files into the SD/Media/Music directory with this.
If the connection is spotty, please do keep in mind you may have to bring the Miyoo Mini Plus closer to your router. For some reason, my router does not like the Miyoo and I have to pretty much place it within arm’s reach of the router for any network functions to work properly.
Installing GMU
Now that Onion OS is installed, we’ll be installing GMU next. To do this, navigate to Apps -> Package Manager -> Apps -> Music Player (GMU) and enable it.
Press Start twice to install it. This will exit out of Package Manager and we’ll be back into the Apps folder again.
Scroll all the way down and we will find the Music Player app icon.
Editing Sleep Timer
Before we start the music app, we do need to make one very important change. Navigate to Settings -> Sleep timer -> off.
If you don’t turn this off, the Miyoo Mini Plus will go to sleep even while playing music unless you are actively pressing buttons. I found the device to be unusable as a mp3 player without turning off the sleep function.
Make sure to turn the sleep timer back on when you are done using the Miyoo Mini Plus as a music player. With this option turned off the device will remain on and will drain the battery if you ever forget to turn it off.
Navigate back to Apps -> Music Player and start it to make sure all the necessary files are created.
Exit Gmu by pressing Menu+Select and get ready to copy our music over to our microSD card.
Supported File Types
Gmu supports Ogg vorbis, mp3, mp2, muse pack, flac, speex, ogg opus, wavpack, and module formats.
m3u and pls playlist files are supported as well. Gmu can write m3u playlists as well but pls playlists can only be read.
If you are going to be using the app to make your playlists, I would recommend separating songs for separate playlists by putting them into different folders.
Editing GMU Settings
I would recommend rebinding previous/next track from L1/R1 to Menu+L1/Menu+R1. The trigger buttons are very easy to press when you have the device in your pocket.
To edit the keybinds, plug your microSD card into your computer and navigate to SD/App/Gmu/miyoo.keymap. Make a backup of the file before making any changes.
Scroll down to PreviousTrack=L1 and NextTrack=R1 and change to PreviousTrack=Mod+L1 and NextTrack=Mod+R1.
You can feel free to change the bindings to whatever you want but do note that the Modifier, Up, Down, Pause, ProgramInfo, Exit, PlaylistPlayItem, PlaylistClear, and FilebrowserAddFiletoPlaylistOrChDir controls must be bound.
Creating Playlists
To create a playlist when in the Gmu app, press Menu+Y on a directory to add all the files to a new playlist from the main Gmu window.
Press Select once to switch to the playlist window.
Press Menu+A to bring up the playlist save/load menu. Select the playlist you want to save it to and press the A button to save.
Now you can load this playlist whenever you want by returning to the playlist save/load menu and pressing Y on the playlist you saved.
Note About Sleeping Display
If you want to change the display timeout, plug your microSD card into your computer and navigate to SD/App/Gmu/gmu.miyoo.conf and make a backup of the file.
Edit SDL.SecondsUntilBacklightPowerOff=20 to any higher number. I changed mine to 60.
Editing Playlist Names
To edit or add playlists, navigate to SD/App/Gmu/gmu.miyoo.conf.
Edit the Gmu.PlaylistSavePreset= list.
Any name changes you made here must match the m3u playlist files in the same directory. For example, if I change the rock.m3u entry to rockandroll.m3u in the configuration file, I need to make sure to change the actual rock.m3u file’s name to rockandroll.m3u as well.
How to Control GMU
Global Controls
A = Play SongStart = PauseLeft/Right = Rewind/ForwardMenu+L1/R1 = Previous/Next Track (We rebound these keys, default is L1/R1)Menu+Select = Exit GmuMenu+Start = Help Screen
Main Window
X = Add Dir to Current PlaylistMenu+Y = Add Dir to New Playlist
Playlist Window
X = Switch Play Mode (continue, repeat all, repeat track, random, random+repeat)Menu+B = Clear PlaylistMenu+A = Save/Load Playlist MenuMenu+Right = Queue Selected SongMenu+L2 = Gmu Info Screen (A to exit)Menu+Down = Toggle Auto Shutoff (15, 30, 60, 90 minutes, After Last Track) – This is currently bugged
Track Window
A = Toggle Display Mode (text + image, text only, text + spectral analyzer)B = Toggle Text On/Off
Experience
As for the experience of using it as a mp3 player, it works fine but it has some minor flaws you may want to consider.
For starters, the audio quality seems to be pretty good. I’m no audiophile and I don’t have good gear, but to my untrained ears it sounds fine. If you plan on using the built in speaker it definitely is subpar.
While the audio is fine, there is a noticeable blip sound when ever a track is finished and it moves on to the next one. It kind of takes me out of the listening experience a little bit. The blip isn’t present when using the skip track function however, only when a track finishes playing to completion.
Secondly, the controls are not ideal for quickly navigating the app while in a pocket and you will have to deal with a lot of unwanted button presses thanks to the sensitive triggers. Thankfully we can rebind the buttons and that alleviates some of the problems but with the rebinding it becomes a bit more difficult to reach into your pocket and operate the device.
If you’re controlling the device while holding it, it’s perfectly fine.
Thirdly, editing config files is not the most user friendly way to make changes. I’m totally fine with tinkering since I’m used to it. For some people this may be a bit too much work just to use the Miyoo Mini as a music player.
Hopefully this guide makes the process much easier to understand.
As a side note, if you guys are planning on using the Miyoo Mini as a MP3 player while working out or moving around a lot, I would definitely recommend making sure it has some sort of case or is secured to your person somehow. The screen is notorious for breaking at the slightest impact. A screen protector wont be enough, you’d need a full case, a bumper case, a lanyard, or heck, even duct tape it to yourself.
Conclusion
Overall, the Miyoo Mini Plus works surprisingly well as a MP3 player. The audio quality is pretty good (other than the blip after each track) and the Gmu app plays back most of the audio formats currently in use and does a good job with just a tiny bit of tweaking needed.
Since the screen is turned off most of the time, you get a decent amount of battery life out of it as well.
Just remember to turn the system sleep timer back on as I know someone out there will forget to turn their device off and wake up to a dead battery.
If you only wanted a dedicated MP3 player, I wouldn’t buy a Miyoo Mini just for this purpose. A dedicated MP3 player is going to be much cheaper and more robust as well as easier to use. However, if you have a Miyoo Mini or a Miyoo Mini Plus and you wanted to listen to music on it, it works pretty well.
Thank you so much for dropping by and reading. I hope this guide was helpful. If you have any questions or comments please feel free to leave one below. I do try to read and respond to every comment. Thanks once again to the Onion team and everyone making these open source apps that are so convenient. As always, hope you guys are staying safe and sane out there and catch you guys next time.
Ducky Obrien 
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