Batocera vs Knulli vs JELOS: The 2026 State of the Ecosystem

If you have spent more than twenty minutes looking at custom firmware for a retro handheld in 2026, you have almost certainly seen all three names: Batocera, Knulli, and JELOS. They share the same EmulationStation frontend, similar menu layouts, and largely the same RetroArch core library underneath. The question of which one to install is not really a taste question — it is mostly a hardware question, and one firmware has functionally ceased to exist.

This overview cuts through the noise. It explains exactly which firmware belongs on which device, why Knulli is not just “Batocera Lite,” and why pointing someone toward a JELOS download in 2026 is doing them a disservice.

What you’ll need

Before anything else, make sure you have the right materials. The requirements below apply across all three firmwares — each uses the same basic SD-card-flash method on handheld hardware.

• A microSD card — class 10 / U3 or faster; check your device’s maximum supported size
• balenaEtcher or Rufus (Windows/macOS/Linux) for flashing
• A second microSD card (recommended) for storing ROMs and BIOS files separately from the OS card
• 30 minutes minimum — per each firmware’s installation time estimate
• Risk level: low on handhelds — flashing to SD is fully reversible; just swap the card back

For Batocera on PC (x86_64), the risk profile is different: a full disk install is destructive. Keep that install path well away from any drive you care about.

Before you start

Recovery is straightforward on all three: if something goes wrong, power off, remove the SD card, and reflash. None of these firmwares touch the device’s internal storage in a way that bricks it. If you have a dual-slot device, keeping the stock firmware card in slot 2 as a fallback costs nothing.

One important note on JELOS specifically: the original project ended in late 2024. The original maintainers no longer release new binaries. Sources remain public and archived, but there is no active build pipeline. If you are reading a guide that treats JELOS as a current, maintained option, that guide is out of date. The active successor is ROCKNIX, and that is what you should install on RK3566 devices going forward.

The three firmwares: what they actually are

Batocera

Batocera Linux is the upstream project — the original. It targets a wide hardware range: x86_64 PCs, Raspberry Pi 3/4/5/Zero/Zero 2 W, ODROID XU4/N2+/Go Advance/Go Super, and various other ARM-based retro devices. Development is active, the license is GPL, and the theme ecosystem is very active.

The EmulationStation frontend, built-in scraper, RetroAchievements support, netplay, PortMaster, Moonlight streaming, and even a PC gaming mode are all confirmed features. If your hardware is on the supported list above, Batocera is the natural choice and you should download it directly from batocera.org/download. SHA256 verification checksums are included in the release notes.

The catch: Batocera cannot legally ship the closed-source GPU and display drivers required on Anbernic’s H700 platform. GPL cannot bundle proprietary blobs. This is not a Batocera failing — it is a licensing reality. For H700 devices, you need Knulli.

Knulli

Knulli is a fork of Batocera created specifically to solve the driver licensing problem. By separating the proprietary driver bundle from the GPL core, Knulli can legally ship functional builds for the Anbernic H700 family and related hardware. The full community codename is KNULLI (FIREFLY).

Supported devices include the RG28XX, RG35XX (multiple variants including the 2024 refresh and SP), RG35XX-H, RG35XX Plus, RG40XX-H, RG40XX-V, RG406H, RG406V, RG-Cube, and the Trimui Smart Pro. That last one matters: Knulli’s cross-device reach including the Trimui Smart Pro is a differentiator versus muOS, which covers only Anbernic hardware.

Feature-wise, Knulli matches Batocera almost entirely: EmulationStation frontend, built-in scraper, RetroAchievements, netplay, PortMaster installed by default, overclocking, and sleep mode. Two features specific to Knulli hardware support stand out: hinge support for the RG35XX SP (closing the clamshell lid triggers sleep), and ADB connectivity for the Trimui Smart Pro. OTA updates are available through the Updates & Downloads menu, which Batocera upstream does not offer in the same form on handhelds.

Difficulty is rated beginner. If you have ever flashed any SD card firmware before, there is nothing new here.

Releases are on GitHub at github.com/knulli-cfw/distribution/releases.

JELOS

JELOS (Just Enough Linux OS) was the leading RK3566 handheld custom firmware through 2023 and into 2024. It had broad device support — RG353P/M/V/VS, RG503, RG351 (RK3326 variant), RG552, Powkiddy RGB30/X55/RGB10 Max 3, and even x86 GPD/AYN devices. The feature set was solid: EmulationStation, RetroAchievements, PortMaster, netplay, overclocking, sleep mode.

The project ended in late 2024. The original maintainers stopped releasing new binaries. The GitHub sources are still public and some archived binaries exist, but there is no active development path.

Do not recommend JELOS to anyone starting fresh in 2026. The correct answer for every device JELOS used to cover is now ROCKNIX, which forked from JELOS and continues active development. Users on a working JELOS installation who do not need updates can stay put — but anyone hitting a bug or wanting new core support should migrate to ROCKNIX.

Side-by-side comparison

Feature	Batocera	Knulli	JELOS
Active development	✅ Yes	✅ Yes	❌ No (ended late 2024)
Frontend	EmulationStation	EmulationStation	EmulationStation
Anbernic H700 support	❌ No (driver licensing)	✅ Yes	❌ No
RK3566 support (RG353 etc.)	Partial	❌ No	✅ Yes (archived)
Raspberry Pi support	✅ Yes	❌ No	❌ No
PC (x86_64) support	✅ Yes	❌ No	Limited
PortMaster	✅ Yes	✅ Yes (default)	✅ Yes
RetroAchievements	✅ Yes	✅ Yes	✅ Yes
OTA updates	Via plugins	✅ Yes (built-in)	❌ No longer
Netplay	✅ Yes	✅ Yes	✅ Yes
Overclocking	✅ Yes	✅ Yes	✅ Yes
Sleep mode	—	✅ Yes	✅ Yes (most devices)
Theme ecosystem	Very active	Active (shared w/ Batocera)	Active (EmulationStation)
Successor to use today	—	—	ROCKNIX

Which one should you install

The decision tree is short:

• Anbernic H700 device (RG35XX SP, RG35XX Plus, RG35XX-H, RG40XX-H/V, RG406H/V, RG-Cube, RG28XX) → Knulli
• Trimui Smart Pro → Knulli
• Raspberry Pi (3/4/5/Zero/Zero 2 W), ODROID, or x86 PC → Batocera direct
• RK3566 device (RG353 series, RG503, Powkiddy RGB30/X55) → ROCKNIX (not JELOS, not covered here — see the ROCKNIX guide)
• RK3326 device (older RG351 family) → Batocera direct or ROCKNIX depending on variant

The overlap in features between Batocera and Knulli is intentional — Knulli is a fork, not a rewrite. If you are already familiar with Batocera on a Raspberry Pi and you pick up an RG35XX SP, Knulli will feel immediately familiar. The EmulationStation layout, scraper workflow, and RetroAchievements setup are identical. The only meaningful difference is that Knulli adds hardware-specific features (hinge sleep, OTA updates on-device) and ships the drivers Batocera legally cannot.

Common questions

Can I run Batocera directly on an RG35XX SP? Not usably. Batocera cannot include the proprietary drivers the H700 SoC requires. You would get a non-functional or severely degraded experience. Install Knulli.

Is Knulli safe to use long-term? Development is active as of this writing. The GitHub releases page has regular updates. The fork is well-motivated (a real licensing constraint, not a drama split) and community adoption is strong.

Should I migrate from JELOS to ROCKNIX? If your device is working and you do not need updates, there is no urgency. But JELOS will never receive another official build. Any new bug, core update, or driver fix will only appear in ROCKNIX going forward. Migration is worth doing.

Do themes transfer between Batocera and Knulli? Yes — Knulli shares the Batocera theme ecosystem, and themes built for one generally work on the other. Knulli ships its own Default-KNULLI bezel bundle with support for 4:3, 1:1, and 16:9 screen configurations out of the box.