muOS, one of the most refined and procedurally updated custom firmware for Anbernic’s RG35XX line of devices, has been updated to improve upon various changes introduced in 2405 Beans. This update brings full support for the fan-favorite RG35XX SP and its smaller cousin, the RG28XX.

muOS Beans on RG35XX SP


An official changelog of new features can be found on the release page. The inclusion of RG35XX SP support comes with the ability to fully utilize the “lid-sleep feature” of the device; automatically putting the device into sleep mode when closed, and naturally waking up when opened.

muOS Changelog

This update makes muOS the third CFW to add support for the lid-sleep feature, with the others being minUI by Shaun Inman and GarlicOS by Black Seraph. The muOS Team has supplied a list of the most significant changes on the release page:

muOS 2405.1 “Refried Beans” Significant Changes

  • Added RG28XX and RG35XX-SP support
  • Added Lid mode support for RG35XX-SP
  • Added Sleep and shutdown mode
  • Added HDMI audio output
  • Added HDMI resolution change
  • Added visual options to remove ( ) [ ] and replace - to : on content names
  • Fixed global configuration corruption for those who like to press the reset button for funsies
  • Fixed network connection to be a bit more stable
  • Themes are now placed in SD1 (MUOS/theme/active) for changing on-the-fly or fixing errors easily
  • Backup Manager and System Refresh have been merged to Task Toolkit
  • Menu is now more responsive
  • Visual indicators for volume and brightness are more accurate
  • muOS is now device agnostic – Reliance on hardcoded pathing is reduced by 90%
    • This will make it easier to support more devices in the future
  • Updated RetroArch to 1.19.1 and multiple core updates
  • Updated secret mode
  • Updated supporter screen

More muOS Additions

Quick Shutdown feature on RG35XX SP

Not only does muOS now include support for Anbernic’s latest, but these devices now support HDMI audio output. Until now, any audio would come from the device, even when plugged into HDMI. With the Refried Beans update, players also gain the ability to adjust their output resolution as well with a choice between the following:

  • 480i
  • 480p
  • 576i
  • 576p
  • 720p 50hz
  • 720p 60hz
  • 1080i 50hz
  • 1080i 60hz
  • 1080p 24hz
  • 1080p 50hz
  • 1080p 60hz

muOS, a newcomer into the scene as far as custom firmware goes, has been receiving updates, bug fixes, and tweaks via its beta channels on their Discord about once a week since the release of the RG35XX SP. The development team relies on community feedback and private testing to perfect and introduce new features with each update.

Refried Beans also features a refined port of DraStic made by Steward Fu originally created for Miyoo devices. By heavily customizing DraStic from its original source, Steward was able to make a version of DraStic that plays optimally on relatively low powered  retro handhelds. Paired with the development team adding various RG35XX specific improvements, DS emulation on muOS should feel smoother and play more optimally

Throughout the entire development process of Beans, the community regularly offers feedback about issues and provides recommendations. Judging by the changelog, it seems a majority of those have found their way into the final release.

Try muOS For Yourself!

If you’re interested in utilizing muOS, check out Andrew’s incredibly in-depth setup guide to get yourself started. muOS offers a sea of features, options, and tools to enable you to make your device work the way you want it to, while still being intuitive and easy to use.

Common features include themes, native Pico-8 support, and support for some common standalone emulators like DraStic, Mupen64 Plus, and ScummVM for Nintendo DS, Nintendo 64, and point-and-click PC games respectively.

What’s Next for muOS?

muOS Banana Voting

As shown by the title being a play on words of their most recent major release, 2405 “Beans” this update was meant to touch up and fix issues that were still present in Beans, while also adding support for consoles released shortly after the release of the custom firmware. Excusing any minor updates Refried Beans may receive in the coming weeks or months, the next major release will be 2407 “Banana” a name chosen by community members in early June.

There is no estimated time for Banana to be released, but its development has been in the works since the initial release of Beans. With Refried Beans out now, a version of muOS with full support for Anbernic’s XX line of consoles is finally here.


Editor’s note: This post was updated to include information about the new version of DraStic featured in Refried Beans.


What are your thoughts on the new muOS update? Are you excited to update, or sticking with another CFW altogether? Tap in with us in the comments below, and come chat with the rest of the community in our Discord!