Key facts
- muOS Andromeda, also numbered MustardOS 2606.0, was released as a stable firmware update with 1,229 recorded changes, which the MustardOS team describes as one of the biggest releases to date.
- Supported devices now total 18, covering the full Anbernic H700 family such as the RG SP and BatleXP G350, plus the GKD Pixel 2, TrimUI Brick, TrimUI Brick Pro and TrimUI Smart Pro.
- MustardOS is a Linux-based custom firmware for supported retro gaming handhelds that aims to replace manufacturer operating systems and add missing functions.
- Users should back up all files on a handheld before installing the update because a fresh install may be needed if something goes wrong.
The MustardOS team released muOS Andromeda, numbered MustardOS 2606.0, as stable firmware on Oct. 24, 2026. The update carries 1,229 recorded changes, which the developers call one of the project’s biggest releases. It follows the previous stable version, Jacaranda, after roughly eight months without a new stable build.
MustardOS is a Linux-based custom firmware built for supported retro handhelds, intended to replace the manufacturer operating system and add functions the original software lacks. The stable build now works on 18 devices. Supported models cover the full Anbernic H700 family including RG SP and BatleXP G350, plus GKD Pixel 2, TrimUI Brick, TrimUI Brick Pro and TrimUI Smart Pro. The wider support means owners of other retro handhelds can use MustardOS instead of the manufacturer-provided firmware.
Pickles, the built-in Libretro player (Libretro is the emulator core framework behind Pickles), adds network play, RetroAchievements support, cheats, overlays, colour filters, controller and port remapping, turbo mode, suspend and resume, and detailed performance monitoring. Direct Link allows two-player Pickles sessions over Ethernet or USB-C cables.
Cores requiring a BIOS now halt at startup and display the missing files. Sega Saturn defaults to the Yabadabadoo core. That core requires saturn_bios.bin, sega_101.bin or mpr-17933.bin placed in the BIOS folder.
The default PICO-8 core is now Picante8, taking over from Retro8. Core Management replaces the Core Downloader for handling Libretro core installation and updates. The project removed the external FreeJ2ME launchers, assigning J2ME content to the FreeJ2ME core that now runs in Pickles.
Wasabi, an integrated media player, handles video, music, playlists, live television and live radio. The player offers bookmarks, an equaliser, visualisers and shaders within the familiar MustardOS look. New screensavers show the date and time, flying box art, an image slideshow and a blue screen. Each one offers a preview through the power settings.
Themes are kept as open folders for quicker switching and now support 1920×1080 resolution, with different colour files, font choices, font shadows and control over the boot logo at startup. Random theme selection at startup returns. The content explorer adds forward history, collection and history actions, options for each item, video previews and a catalogue supporting SVG artwork and text manuals. SVG is a scalable image format.
First-time setup includes an orientation tour of every screen. The system adds an activity tracker and passcode settings, along with bulk storage tools. Users can configure ports for each Web Service (online services a handheld can connect to). Bluetooth support arrives at the operating system level for compatible hardware.
The system now saves backups as .muxbak files in ARCHIVE instead of BACKUP, and each backup carries a checksum manifest checked before restoration. Older .muxzip backups skip the check but install after users copy them from BACKUP into ARCHIVE. Opening the Archive Manager and pressing MENU on a backup reveals what it contains. A failed backup or installation writes a log to MUOS/log on SD1.
Users should back up every file on a handheld before installing because the update may require a fresh install if something goes wrong. Test builds from Oct. 7 to Oct. 16 that saved MustardOS Settings left those sections empty, so users cannot restore the data and should create a fresh backup after setup. Theme files saved as .muxthm in MUOS/theme need manual extraction because the system now stores them as open folders rather than compressed archives.
H700 owners who connect a charger while the device is off will find that it no longer starts the system. The device can recover through a safe mode boot guard after repeated failed starts.
Users can download the firmware from Gofile, MEGA or Filen on the project’s release page. The published changelog records 1,229 changes, though the developers say more modifications exist beyond what is documented.
The release credits contributors including 0xada.3, antikk, artur_ditu, bgelmini, bitter_bizarro, corey, imcokeman, key777, mugwomp93, saitamasahil, thewalruzz, xikteny and xonglebongle. Support links appear for crew members AntiKk, Corey and Bitter Bizarro.
People can join the testing crew: supporting XongleBongle through Ko-fi, boosting the Discord server, submitting major code pull requests or acting as a positive community member. People can back MustardOS by joining the Community Forum, being useful on the Discord Server, adding code to GitHub Repositories or spreading the word. Gameforce Mobile states that the release shows how software made by the community can greatly increase the value of low-cost handheld gaming hardware without needing a faster processor.
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