Anbernic, Retroid, and TrimUI have shipped more retro handhelds in the past 18 months than the entire market released between 2015 and 2022, and the firmware running on those devices has splintered into three real camps. Knulli, Batocera, and muOS now cover almost every $50-to-$200 emulation handheld sold in 2026, but they take different bets on speed, breadth, and how fast a brand-new device gets supported. Knulli shipped its SCARAB build on May 11, 2026, adding official support for the Miyoo Flip, Retroid Pocket 5, and GKD Pixel 2 within weeks of their retail launches. Batocera’s 43.1 “Glasswing” release, current since May 30, 2026, still ships more than 200 emulated systems out of the box across everything from a Raspberry Pi to a Capcom Home Arcade cabinet. muOS, running its 2601.1 “Funky Jacaranda” build — identified as the project’s current stable release as of August 2026 — stays deliberately narrow, targeting Anbernic’s RG35XX family and the TrimUI Brick and Smart Pro with a from-scratch codebase instead of Batocera’s inherited one.
This is not a rehash of a Switch emulator fight or a PS3 compatibility chart. Knulli, Batocera, and muOS are operating systems, not single-console emulators. They decide which cores load, which controllers get recognized on first boot, and whether a $60 handheld from Anbernic behaves like a finished product or a half-supported science project. With Nintendo’s own console emulators under sustained DMCA pressure throughout 2026, the firmware layer underneath a physical handheld has become the more stable, more legally uncomplicated way for a lot of players to run their existing game libraries. Here is what the version numbers, device lists, and GitHub activity actually show as of September 30, 2026, and how these three fit into the broader handheld and mobile gaming landscape shaping 2026.
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What Handheld Emulation Firmware Actually Does
A handheld emulation firmware is a full Linux-based operating system that replaces (or dual-boots alongside) whatever a manufacturer preloaded on a device. Anbernic, Powkiddy, and most other budget handheld makers ship a stock OS that is functional but limited: fewer emulator cores, clunky theming, and BIOS configuration that often needs manual file editing. Knulli, Batocera, and muOS exist to fix that gap by bundling a pre-configured frontend (usually EmulationStation or a fork of it), a curated set of emulator cores, controller mapping that works without touching a config file, and an update path that keeps pace with new hardware releases.
The three projects share more code than most buyers realize. Knulli is a direct fork of Batocera, meaning its frontend, RetroArch integration, and core menu structure trace back to the same codebase. muOS took the opposite path: it was built from scratch specifically for a narrower list of Anbernic and TrimUI hardware, trading Batocera’s sprawling platform list for a lighter footprint and faster boot times on the handhelds it does support. That single design decision explains almost every practical difference covered in this comparison, from install complexity to how quickly each project can add support for a device that just came out of a factory in Shenzhen.
Why this matters more in 2026 than it did two years ago comes down to two separate market forces colliding. First, the sub-$100 handheld category exploded, with Anbernic, Powkiddy, Miyoo, Retroid, and GKD all shipping multiple new models through 2025 and 2026, often with barely-adequate stock firmware that gets replaced within days of a device reaching buyers’ hands. Second, Nintendo’s escalating legal campaign against console-specific Switch emulators, which wiped out more than 400 GitHub repositories in a single coordinated sweep on August 17, 2026, pushed a portion of the emulation community toward the comparatively less contentious world of dedicated retro handhelds running open, general-purpose firmware instead of chasing console-specific software through repeated takedowns. A firmware project that legally bundles open-source cores for systems from the 1980s and 1990s carries none of that same legal exposure, which is part of why Knulli, Batocera, and muOS have all seen steady growth in device support and community attention through the back half of 2026.
Knulli: The Fast-Moving Batocera Fork
Knulli’s GitHub description frames its mission plainly: take the free, GPL-compliant Batocera codebase and use it to properly support handhelds that usually ship with incomplete or non-compliant software out of the box. That mission has translated into an aggressive device-support cadence. The project’s most recent major build, SCARAB (20260511), released May 11, 2026, and its rolling changelog has kept adding to that base well past the initial release: an October 2026 update folded in H700-chipset support alongside a bump to RetroArch 1.22.2, and that same October refresh added seven or more newly supported handhelds, including the Anbernic RG28XX and RG34XX, plus the BattleXP G350, GKD Pixel 2, Miyoo Flip, Powkiddy X55 and RGB30, and Retroid Pocket 5, Flip 2, and Mini/Mini V2, and an early alpha build for the TrimUI Smart Pro S.
That list matters because most of those handhelds launched in 2025 and 2026, well after muOS and Batocera had already settled on their supported hardware. Knulli’s official device page, hosted at knulli.org, is organized by exact device model and warns users not to flash an image built for a different variant, since Anbernic and Powkiddy frequently ship near-identical shells with different internal chipsets. As of September 30, 2026, the project’s main repository at github.com/knulli-cfw/knulli-linux had accumulated 285 GitHub stars, based on the repository’s own star counter visible on its issue tracker. That is a modest number next to older, more established open-source projects, but Knulli itself is still a comparatively young fork, and its star count has been climbing steadily as new devices get added to its release notes.
One structural detail worth knowing before installing Knulli: the project’s original repository, then named knulli-cfw/distribution, was archived by its owner on June 16, 2026 and marked read-only after development moved to the current knulli-linux repository. That is a routine repository rename rather than a project shutdown, but anyone following old links or forum posts from earlier in 2026 may land on the archived repo and assume the project is dead. It is not. Release activity on knulli-linux continued through September 2026, including active GitHub issue threads such as one from Powkiddy A12 owners troubleshooting a Wi-Fi dongle and SHARE partition problem, which is the kind of unglamorous, ongoing support work that signals a project still being actively maintained rather than coasting on an old release.
The other thing worth understanding about Knulli is why it exists as a separate project instead of just being a set of pull requests submitted back to Batocera. Batocera’s own release cadence is deliberately measured, covering a huge platform matrix that stretches well beyond handhelds, which means a niche new device from a small Chinese manufacturer can sit in a backlog for months before it gets a supported image. Knulli’s maintainers effectively decided to specialize: strip the ambition down to handhelds specifically, and move fast on exactly the devices that show up on AliExpress and Amazon listings weeks before mainstream coverage catches up. That specialization is also why Knulli’s device page insists on exact model matching rather than broad family support, since a handheld like the Anbernic RG35XX line has shipped with at least three distinct internal chipset revisions under similar-looking shells, and a mismatched image is a fast way to end up with a bricked SD card rather than a working handheld.
Batocera: The Broadest Emulation Platform Around
Batocera is the elder of the three and the one neither Knulli nor muOS could have existed without. The “Glasswing” codename belongs to the whole 43-series line, which launched as 43.0 on May 8, 2026 and was followed three weeks later by Batocera 43.1 “Glasswing,” which has held the top spot on the official download page since May 30, 2026 and is still Batocera’s current listed release as of October 2026. That same 43 release added initial support for the AYN Thor, Odin 2 Mini, and Retroid Pocket 6 back in May 2026, underscoring that Batocera is still chasing newer handhelds even as Knulli specializes in them. This site’s own step-by-step Batocera install guide walks through flashing that exact release for anyone starting from scratch. Where Knulli and muOS focus almost entirely on handhelds, Batocera’s ambition is different: it targets PCs, Raspberry Pi boards, Odroid single-board computers, generic ARM development boards, and handhelds side by side, with its official download page listing everything from the Powkiddy A12 and A13 to the Odroid Go Super to, unusually, a Capcom Home Arcade cabinet build.
That breadth shows up in the numbers people actually cite about the project. Batocera 43.1 ships with more than 200 emulated systems configured out of the box, a figure the project has repeated across its recent release notes and that Batocera’s own compatibility page backs up with a granular, per-system status table rather than a single marketing claim. The compatibility page is refreshingly blunt about limitations, too, flagging specific device-and-system combinations with a “low performance for some games” qualifier instead of implying universal perfection. Batocera’s own homepage describes itself in equally direct terms, stating that the OS is ready for use and supports most controllers out of the box, a claim borne out by its long track record as the base layer other projects, including Knulli, chose to build on rather than write from scratch.
Batocera’s official documentation at wiki.batocera.org also confirms two features that matter for competitive and social retro gaming: a dedicated RetroAchievements settings menu for tracking in-game accomplishments across supported RetroArch cores, and a built-in netplay submenu for online multiplayer sessions. Both are documented, first-party features rather than community add-ons, which is a meaningful distinction from smaller projects where the same functionality might depend on a manually installed core update.
Batocera’s changelog also shows it has not stopped expanding its board support just because handheld-specific forks now exist to chase newer devices. The project added initial support for the Dockerpi Powerboard on the Raspberry Pi 3 and for the OrangePi 5 Pro single-board computer, both logged in its 43.x-era changelog. That is not the kind of update a handheld buyer cares about directly, but it illustrates the core difference in scope between Batocera and its two handheld-focused descendants: Batocera’s maintainers are still building for hobbyists wiring together bare circuit boards and arcade cabinets, not just flashing an SD card for a pocket-sized clamshell. For anyone whose retro setup includes a home-built arcade cabinet, a media-center PC doing double duty as an emulation box, or a Raspberry Pi tucked behind a TV, that breadth is the entire reason to pick Batocera over either handheld-specialized alternative.
muOS: Built From Scratch for Speed and Simplicity
muOS, also known as MustardOS, takes the narrowest scope of the three by design. Its official device page at muos.dev lists the current build as 2601.1 “Funky Jacaranda,” using a year-month version numbering scheme where the “2601” prefix traces back to the 2601.0 “Jacaranda” release that shipped in February 2026; that original 2601.0 build was itself archived in October 2026 once the Funky Jacaranda point release took over as the supported line. muOS focuses almost entirely on Anbernic’s RG35XX family, including the original RG35XX, the RG35XX Plus, RG35XX H, the 2024 hardware refresh, RG35XX SP, RG35XX Pro, plus the RG28XX, RG34XX, RG40XX H and V, and RGCubeXX, along with the TrimUI Brick and TrimUI Smart Pro.
That narrower target list is the entire point. Because muOS is not carrying Batocera’s code for PC boards, Odroid hardware, or dozens of other single-board computers, it can tune its build specifically for the chipsets found in a handful of Anbernic and TrimUI devices, which is why community discussion, and this site’s own earlier comparison of muOS against ArkOS and JELOS, consistently describes it as the lightest, fastest-booting option of the group on the hardware it actually supports. The tradeoff is obvious: buy a device outside that list, such as a Retroid Pocket 5 or a Miyoo Flip, and muOS simply is not an option, while Knulli likely already has a build.
muOS’s version-numbering habit is also worth flagging for anyone comparing changelogs across projects. Where Knulli uses named builds tied to a numeric release date (SCARAB 20260511) and Batocera uses a simple major.minor scheme (43.1), muOS labels its releases with a year-month code followed by a nickname, so “2601.1 Funky Jacaranda” reads as the first point release of the build line that started in January 2026, according to the version history on the project’s own roadmap page, which also lists an earlier “2502 Pixie” release line. That numbering quirk matters mostly for support purposes: if a community thread references a muOS build number, matching it to an actual calendar date takes an extra step compared with checking Knulli’s or Batocera’s more conventional versioning.
Specs Comparison: Knulli vs Batocera vs muOS
The table below pulls directly from each project’s official release pages, GitHub repositories, and documentation as of late September 2026.
| Category | Knulli | Batocera | muOS |
|---|---|---|---|
| Latest version | SCARAB (build 20260511) | 43.1 “Glasswing” | 2601.1 “Funky Jacaranda” |
| Release date | May 11, 2026 | May 30, 2026 (43.0 shipped May 8, 2026) | Current as of Sept. 22, 2026 device-page update |
| Codebase origin | Fork of Batocera | Original project (independent Linux distro) | Built from scratch, not Batocera-derived |
| License | Open source (inherits Batocera’s GPL-compliant base) | Free and open source | Free and open source |
| GitHub stars | 285 (Sept. 30, 2026, knulli-linux repo) | Not independently verified this cycle | Not independently verified this cycle |
| Emulated systems out of the box | Inherited Batocera core set, expanded per device image | 200+ systems configured by default | Narrower, curated set tuned to supported handhelds |
| Primary hardware focus | Newest handhelds: Anbernic, Miyoo, Powkiddy, Retroid, GKD | PCs, SBCs, and handhelds together (broadest scope) | Anbernic RG35XX family + TrimUI Brick/Smart Pro only |
| Newest 2026 device wins | Miyoo Flip, Retroid Pocket 5/Flip 2/Mini, GKD Pixel 2 | Continued board support (Dockerpi Powerboard, OrangePi 5 Pro) | Consistent support for existing Anbernic/TrimUI lineup |
| RetroAchievements | Available via inherited RetroArch cores | Officially documented, dedicated settings menu | Not independently confirmed from official docs this cycle |
| Netplay | Available via inherited RetroArch/EmulationStation base | Officially documented, dedicated netplay menu | Not independently confirmed from official docs this cycle |
| Install method | Device-specific SD card image, exact model match required | Board/device-specific SD card or USB image | Device-specific SD card image |
| Repository status | Active; earlier “distribution” repo archived June 16, 2026 after rename | Active since 2012-era origins | Active, ongoing device-page updates |
A few things stand out immediately. Knulli and Batocera both officially confirm RetroAchievements and netplay because Knulli inherits the same RetroArch integration Batocera documents directly on its wiki. muOS’s own site did not surface an equivalent first-party feature page in this research pass, which does not mean the features are absent, only that they were not confirmed the same way. Readers who need those two features specifically should check muOS’s release notes for their target device before assuming parity.
Which Handhelds Each Firmware Actually Supports
Device support is the single biggest practical differentiator between these three projects, and it splits almost entirely along the “new hardware” versus “established hardware” line.
- Knulli’s fastest-growing support: Miyoo Flip, Retroid Pocket 5, Retroid Pocket Flip 2, Retroid Pocket Mini and Mini V2, GKD Pixel 2, Powkiddy X55 and RGB30, BattleXP G350, MagicX Xu mini-m, and the R36S, all added or refined in the May 2026 SCARAB release alone.
- Batocera’s widest net: Powkiddy A12 and A13, Odroid Go Super, standard PC and x86 hardware, Raspberry Pi boards, Odroid single-board computers, and niche targets like the Dockerpi Powerboard and OrangePi 5 Pro, both added as initial support in the 43.x changelog.
- muOS’s tight focus: the full Anbernic RG35XX lineup (original, Plus, H, 2024 refresh, SP, Pro), RG28XX, RG34XX, RG40XX H/V, RGCubeXX, plus the TrimUI Brick and TrimUI Smart Pro, and nothing meaningfully beyond that list.
The practical rule of thumb: if a handheld launched in the last six months and it is not an Anbernic RG35XX-family device, check Knulli’s device page first. If it is an older, well-established Anbernic model or a TrimUI handheld and you want the lightest possible firmware, muOS is worth trying. If the goal is running the same emulation setup across a handheld, a Raspberry Pi, and an old PC in the closet, Batocera is the only one of the three built for that job, a distinction covered in more depth in this site’s Batocera vs RetroPie vs Recalbox comparison.
Performance and Update Cadence: What the Data Shows
None of the three projects publish standardized frame-rate benchmarks against each other, so any comparison built on invented FPS numbers would be fiction. What can be measured, from three separate sources, is update cadence and how each project documents real-world performance limits, which is a more honest signal than a single synthetic benchmark score.
First, from Batocera’s own compatibility page: the project does not claim universal perfect performance. Its system-by-system compatibility table explicitly flags select device-and-emulator combinations with a “low performance for some games” note, which is a more transparent approach than a blanket “fully supported” label. Second, from Knulli’s GitHub release history: the SCARAB build landed May 11, 2026, following a steady cadence of device-focused releases going back through 2025, showing a project that ships incremental hardware support rather than infrequent, monolithic updates. Third, from muOS’s own release roadmap page: the project uses sequential year-month builds (2601.1 following the 2502-era “Pixie” release documented on its roadmap), indicating regular, dated iteration rather than sporadic pushes.
A fourth data point comes from third-party repository trackers monitoring Knulli specifically: independent snapshots recorded the project’s star count climbing by roughly 54 stars across 37 tracked snapshots leading into late September 2026, a growth signal that lines up with its expanding device list rather than a one-time spike. None of this substitutes for a controlled frame-time test on identical hardware, and readers chasing exact FPS numbers for a specific game on a specific chipset should check that device’s dedicated subreddit or Discord rather than take any general claim at face value.
RetroAchievements, Netplay, and Everyday Features
Batocera’s documentation at wiki.batocera.org is the clearest of the three on this front. It confirms RetroAchievements is built into RetroArch and supported by a selection of cores, with a dedicated settings submenu for logging in and tracking progress across supported systems. The same documentation tree lists a netplay submenu for configuring online multiplayer sessions, both features accessible directly from the EmulationStation-derived menu structure rather than requiring a manual core swap.
Because Knulli forks Batocera’s codebase wholesale, the same RetroArch core infrastructure travels with it, which is why RetroAchievements and netplay are reasonably expected to function on Knulli builds wherever the relevant cores are packaged into that specific device image. That is an inference based on shared code, not a separate first-party confirmation from Knulli’s own release notes, so anyone relying on either feature for a specific handheld should verify it works on their exact device image before assuming it just carries over.
muOS’s official device documentation did not surface an equivalent first-party statement on RetroAchievements or netplay in this research pass. That is a documentation gap in what was available to verify, not evidence the features are missing, and it is exactly the kind of detail worth checking on muOS’s own release notes for a specific handheld before choosing it purely for feature parity with Batocera or Knulli.
Community and Documentation: How Each Project Communicates Updates
How a project documents itself is a decent proxy for how easy it will be to troubleshoot at 11 p.m. when a new handheld refuses to boot. All three projects publish their release notes and device lists in public, but the depth and format differ enough to matter for a first-time flasher.
| Documentation source | What it covers | Format |
|---|---|---|
| Knulli device page (knulli.org/devices) | Per-model device list, organized by manufacturer and exact chipset revision | Structured wiki-style page with explicit warnings against cross-flashing incompatible images |
| Knulli GitHub changelog (knulli-linux repo) | Release-by-release device additions, bug fixes, and alpha-status flags | Standard GitHub release notes with per-device tables |
| Batocera compatibility page (batocera.org/compatibility.php) | System-by-system, device-by-device performance and support status | Granular table including explicit “low performance for some games” flags |
| Batocera wiki (wiki.batocera.org) | Menu-by-menu breakdown of EmulationStation settings, including RetroAchievements and netplay setup | Structured technical wiki with exportable PDF pages |
| muOS device page (muos.dev/devices) and roadmap | Currently supported handheld models and release-line history | Simple device list plus a separate versioned roadmap page |
Batocera’s documentation is the most granular of the three specifically because its compatibility page tracks performance status per system rather than issuing a single blanket “supported” label. Knulli’s strength is release-note specificity, since its changelogs name the exact devices added in each build rather than describing changes in general terms. muOS’s documentation is the leanest of the three, which fits its overall philosophy: fewer supported devices means less need for an exhaustive compatibility matrix, but it also means troubleshooting a muOS-specific issue may involve more community forum searching than checking an official page.
Pricing: The Firmware Is Free, the Hardware Isn’t
All three firmwares are free, open-source downloads with no license fee, subscription, or paywall of any kind. The real cost of running any of them is the handheld itself, and that is where the comparison gets genuinely useful for a buying decision.
| Handheld | 2026 retail price (USD) | Firmware fit |
|---|---|---|
| Anbernic RG35XX Plus | $49.99 sale / $63.99 regular (Anbernic store) | muOS (official target device) |
| Anbernic RG35XX SP | $54.99 (Anbernic store) | muOS (official target device) |
| TrimUI Brick | Approx. $60-85 depending on SKU/retailer | muOS official; Knulli alpha support for Smart Pro S variant |
| Miyoo Flip | $59.99 (official Aug. 2026 price) | Knulli (added in SCARAB, May 2026) |
| Retroid Pocket 5 | $199 (GoRetroid direct) | Knulli (added in SCARAB, May 2026) |
| Powkiddy A12/A13 | Not independently verified this cycle | Batocera (official download target) |
| Knulli firmware | $0 (free download) | N/A |
| Batocera firmware | $0 (free download) | N/A |
| muOS firmware | $0 (free download) | N/A |
Two pricing sources disagreed on the TrimUI Brick specifically: one 2026 comparison listed it around $60, while another retailer listing showed a base SKU starting from $84.99. That gap is almost certainly a matter of bundle contents, storage capacity, or regional retailer markup rather than a single official price changing, so treat any TrimUI Brick price as a range rather than a fixed number until confirmed at the point of purchase. For a closer breakdown of how the Brick compares to two of its closest handheld rivals on hardware alone, see this site’s RG35XX vs Miyoo Mini Plus vs TrimUI Brick comparison.
Five Real Handheld Setups People Are Actually Running
These are not hypothetical pairings. Each combination below is directly documented in official release notes, changelogs, or public support threads from the projects themselves.
- Anbernic RG35XX Plus running muOS 2601.1: the textbook use case muOS was built for: a $50-to-$64 clamshell handheld, lightweight firmware, and official first-party support with no workaround images required.
- Retroid Pocket 5 running Knulli SCARAB: a $199 Android-adjacent handheld that Knulli added official support for in its May 2026 release, months after the device’s own retail launch, giving buyers a non-Android emulation path.
- Miyoo Flip running Knulli SCARAB: the $59.99 clamshell added to Knulli’s supported-device list the same release cycle it hit retail in August 2026, illustrating how quickly the fork can move on brand-new hardware.
- Powkiddy A12 running Batocera: a real, currently active support thread on Knulli’s own GitHub tracker (issue #91) shows a Powkiddy A12 owner troubleshooting a Wi-Fi dongle and SHARE partition problem, evidence this exact device-and-firmware pairing sees genuine day-to-day use rather than existing only on a compatibility chart.
- TrimUI Smart Pro S running an early Knulli alpha build: flagged explicitly as alpha-stage in Knulli’s SCARAB changelog, a useful reminder that “supported” does not always mean “stable,” and early adopters on newer TrimUI hardware should expect rougher edges than an Anbernic RG35XX running the same firmware for years.
How to Migrate Between Knulli, Batocera, and muOS
Because none of these three firmwares run as an installed app on top of a stock OS, in the way a Windows program might, “migrating” really means flashing a new image and carrying your data across. The process is broadly the same regardless of which direction you are moving.
- Back up your existing SD card first. Copy the entire ROMs folder, any save states, and your RetroArch or EmulationStation config folder to a computer before touching anything.
- Confirm your exact handheld model and chipset revision. Anbernic in particular ships multiple internal hardware revisions under the same model name, and each project’s device page (knulli.org/devices, batocera.org/download, or muos.dev/devices) requires matching the image to the specific revision, not just the model name on the box.
- Download the correct device-specific image from the target project’s official release page, never a third-party mirror, since these images bundle low-level board support that has to match your exact hardware.
- Flash the new image to a fresh, separate SD card using a standard imaging tool such as Balena Etcher or Rufus, rather than overwriting your old card, so you have an instant fallback if the new firmware has issues.
- Boot the handheld from the new card and complete first-time setup, including Wi-Fi and controller calibration if prompted.
- Copy your ROMs folder back onto the new card’s expected directory structure. This layout differs slightly between Batocera-derived systems (Knulli, Batocera) and muOS’s from-scratch layout, so check each project’s folder-naming documentation rather than assuming identical paths.
- Reinstall BIOS files into the correct system-specific folders. None of the three ship copyrighted BIOS files themselves. Users are expected to source their own from hardware they legally own.
- Re-pair any RetroAchievements or netplay account settings, since these are stored per-installation and do not carry over automatically between different firmware projects even on the same physical device.
- Test a handful of games across a few different systems before committing to the new firmware full-time, and keep the old SD card as a backup for at least a few weeks.
Moving from Batocera to Knulli, or the reverse, tends to be the smoothest path since both share the same underlying folder conventions and RetroArch core structure. Moving to or from muOS involves more manual folder reorganization precisely because it was not built on Batocera’s foundation.
For reference, a typical Batocera-derived (Knulli or Batocera) SD card layout separates ROMs by system folder name, which is the structure to check against before copying a library over from a different frontend:
/userdata/roms/snes/
/userdata/roms/genesis/
/userdata/roms/gba/
/userdata/roms/psx/
/userdata/bios/
/userdata/saves/
/userdata/system/configs/retroarch/muOS uses a different top-level structure built around its own storage partition layout, so a folder-for-folder copy from a Batocera-derived card will not drop files in the right place. Always check the specific project’s current folder documentation for your device image rather than assuming the paths above apply universally, since manufacturers occasionally customize the storage layout even within the same firmware project.
Pros and Cons of Each Firmware
Knulli
- Pros: fastest official support for brand-new 2025-2026 handhelds like the Miyoo Flip and Retroid Pocket 5; inherits Batocera’s mature RetroArch/EmulationStation base; active, visible GitHub issue tracking on real hardware problems.
- Cons: smaller community footprint than Batocera (285 GitHub stars as of Sept. 30, 2026); some of its newest device builds are explicitly alpha-stage; requires exact device-revision matching that can trip up first-time flashers.
Batocera
- Pros: broadest platform scope of the three, spanning PCs, SBCs, and handhelds; 200+ systems configured out of the box; officially documented RetroAchievements and netplay; longest track record of the three projects.
- Cons: its own compatibility page acknowledges “low performance for some games” on certain device/system pairs; broader scope means slower turnaround on niche, brand-new handhelds compared to Knulli’s tighter handheld focus.
muOS
- Pros: lightweight, from-scratch build tuned specifically for its supported hardware; consistently described in community comparisons as fast and responsive on the Anbernic RG35XX family and TrimUI Brick/Smart Pro.
- Cons: the narrowest device list of the three by far; no official support outside its established Anbernic and TrimUI lineup; RetroAchievements and netplay support were not independently confirmed from official documentation in this research pass.
Who Should Use Which Firmware
- Buying a brand-new 2026 handheld outside the Anbernic RG35XX family: check Knulli’s device page first. Its SCARAB release cycle proved it can support hardware within weeks of retail launch.
- Running emulation across a handheld, a Raspberry Pi, and an old desktop: Batocera is the only one of the three actually designed for that multi-platform spread.
- Buying an Anbernic RG35XX-family device or a TrimUI Brick specifically for lightweight, fast-booting emulation: muOS’s from-scratch build is the leaner option on that specific hardware.
- Prioritizing RetroAchievements and online netplay above everything else: Batocera has the clearest first-party documentation confirming both features work as advertised.
- Buying a Powkiddy handheld: Batocera is the officially documented target for the A12 and A13, with an active community support thread already troubleshooting real hardware quirks.
- Wanting the newest possible device support with the understanding that some builds are alpha-stage: Knulli, with the caveat to double-check whether your specific device’s build is marked stable or experimental in its changelog.
The Verdict: Picking a Firmware Based on the Numbers
There is no single winner here, and pretending otherwise would misrepresent what the data actually shows. Batocera wins on raw scope: 200+ systems out of the box, support stretching from PCs to single-board computers to handhelds, and the only one of the three with clearly documented RetroAchievements and netplay menus. Knulli wins on speed to market for new hardware, proven by its May 2026 SCARAB release adding official support for the Miyoo Flip and Retroid Pocket 5 within months of their launches, a turnaround Batocera and muOS simply have not matched on those specific devices. muOS wins on focus, delivering a from-scratch build tuned tightly enough to the Anbernic RG35XX family and TrimUI Brick/Smart Pro that it remains the community’s go-to answer for lightweight performance on that specific hardware list.
The practical decision comes down to what you already own or are about to buy. Owners of an established Anbernic RG35XX-family handheld with no interest in exotic hardware get the most out of muOS. Anyone running a mixed fleet of devices, or wanting the deepest feature set with the least uncertainty, should default to Batocera. Anyone who just bought one of 2026’s newest handhelds and found the box firmware lacking should check Knulli first, since its device-support cadence is currently the fastest of the three. And for anyone still choosing the handheld itself before worrying about firmware, this site’s emulation handheld buying guide is the logical starting point.
Frequently Asked Questions
Is Knulli, Batocera, or muOS illegal to install?
No. All three are open-source operating systems and do not include copyrighted BIOS files or games. Installing any of them on a handheld you own is legal. How you source ROMs and BIOS files separately is a distinct legal question that depends on your jurisdiction and whether you own the original hardware or media.
Can I run Knulli or muOS on a device officially supported by Batocera, like a Powkiddy A12?
Only if the other project explicitly lists that exact device on its own supported-hardware page. Batocera’s broader platform list does not automatically mean Knulli or muOS support the same board, since each project maintains its own separate device compatibility list.
Does switching firmware delete my save files?
Flashing a new SD card image does not touch your old card, but moving to that new card means manually copying your ROMs, save states, and BIOS files over, since the three projects use their own folder structures that do not automatically inherit from one another.
Which firmware updates most often?
Based on public release history, Knulli has shipped the most frequent hardware-specific updates through 2026 as it races to support new handhelds, while Batocera and muOS both follow more measured, dated release cycles (43.x for Batocera, year-month builds like 2601.1 for muOS).
Do any of these support RetroAchievements?
Batocera’s official documentation confirms RetroAchievements support through RetroArch cores with a dedicated settings menu. Knulli inherits the same RetroArch base, so the feature is expected to function similarly, though this was not separately confirmed in Knulli’s own release notes. muOS’s official documentation did not surface an equivalent confirmation in this research pass.
Is Knulli actually a separate project from Batocera, or just a theme?
It is a genuine fork with its own release cycle, device list, and GitHub organization (knulli-cfw), not a cosmetic skin. It shares Batocera’s underlying code but makes independent decisions about which hardware to support and how quickly.
Why did Knulli’s original GitHub repository get archived?
The project’s original repository, knulli-cfw/distribution, was archived and marked read-only on June 16, 2026 after development consolidated into the current knulli-cfw/knulli-linux repository. It reflects a repository reorganization, not the project ending.
Which one should a first-time retro handheld buyer choose?
Check the exact device first. If it is a well-established Anbernic RG35XX model or a TrimUI Brick, muOS is the simplest, lightest option. If it is a newer or less common handheld, check Knulli’s device list before assuming it is unsupported. If in doubt, or if the plan includes emulating on a PC or SBC too, Batocera’s broader scope is the safer default.
Can I dual-boot two of these firmwares on the same handheld?
Most of these handhelds use a removable microSD card as the boot device, so the simplest form of “dual-booting” is keeping two separate cards, one per firmware, and swapping them when powering the device on. Some devices support booting from internal storage plus a card, but that varies by model and is not something any of the three projects officially standardize across every supported device.
Does a faster firmware always mean better game compatibility?
No. Boot speed and interface responsiveness are separate from per-game emulation accuracy, which depends on the underlying emulator core, not the frontend wrapped around it. A lighter firmware like muOS can feel snappier navigating menus while still running the same RetroArch cores, with the same compatibility quirks, as Batocera or Knulli on comparable hardware.
