RetroCompass
RetroCompass

Miyoo Mini — Custom firmware

Quick answer

Steps

  1. 1Stock (Linux): the default Miyoo OS — keep it only if you want the out-of-box menu.
  2. 2Onion OS: the flagship CFW for the Mini — RetroArch front-end, themes, box art and 100+ emulators.
  3. 3MinUI: a minimalist launcher — copy MinUI.zip (do not unzip) plus the Bios/Roms/Saves folders to a FAT32 card.
  4. 4Pick one CFW per SD card and back up saves before switching firmware.
Last verified: 2026-06-20Source: onionui.github.io

The Miyoo Mini runs a Linux-based stock OS, but its reputation comes from community firmware. Onion OS is the de-facto choice on this SigmaStar device: a polished RetroArch front-end with themes, box art and an installer that sets everything up on first boot. MinUI is the leading minimalist alternative — almost no menus, very fast, and it shares one card across many handhelds. Because all firmware lives on the microSD, you can swap between them by reflashing the card; nothing overwrites the stock system permanently. Note the original Mini has no Wi-Fi, so Onion's online features (OTA, netplay, scraping) are not available on it.

FAQ

Onion OS or MinUI — which should I choose?
Onion OS if you want box art, themes and full RetroArch options; MinUI if you want a stripped-down, fast launcher with almost no configuration. Both are free and install to the microSD.
Does installing custom firmware brick the original Mini?
No. The Mini boots from the microSD, so CFW lives on the card. If something goes wrong you reformat the card and reinstall — the device itself is hard to brick this way.
Can I keep stock and Onion OS at the same time?
Not on one card — each SD card holds one firmware. Use a second card (or reflash) to switch between stock, Onion OS and MinUI.

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