Firmware Guide
muOS vs Knulli for Anbernic H700 Handhelds: Which to Install
Two custom firmwares target the Anbernic H700 family (RG35XX SP, Plus, H, SP). Direct comparison of features, interface, and emulation configuration.
Zürich, Switzerland
Published April 22, 2026
If you’ve just picked up an Anbernic RG35XX SP, RG35XX Plus, or another H700-class handheld, you’ll hit the same fork in the road within the first week: muOS or Knulli? Both target the same hardware, both are free, both replace the stock Anbernic launcher with something meaningfully better. But they take different philosophies, and choosing the wrong one means reflashing in a month when you realise you’ve picked the one that doesn’t match how you actually use the device.
This guide does a direct comparison. It’s written for someone comfortable formatting an SD card but not necessarily familiar with Linux internals. You don’t need to know how either firmware works under the hood — you need to know which one to install tonight.
What you’ll need
Both firmwares share essentially the same installation requirements:
- A microSD card of at least 16 GB, Class 10 / A1 speed rating or faster
- A second microSD card recommended for game storage (muOS strongly recommends this; Knulli supports it)
- balenaEtcher or Rufus for flashing the image
- About 30 minutes for download, flash, and first boot
- Risk level: low — both are fully reversible by reflashing the stock Anbernic image
Neither firmware requires touching the internal storage of the device. If something goes wrong, you pull the card, flash stock, and you’re back to square one.
Before you start
Neither muOS nor Knulli wipes any internal storage — these devices have none in the traditional sense; everything lives on the microSD. The destructive step is flashing the image onto whichever card you designate as your OS card. Keep your stock card as a backup if you have a spare.
Step 1: Download the firmware
muOS: Official releases are at github.com/MustardOS/frontend/releases. SHA256 hashes are included in the release notes — verify before flashing. Download the correct build for your device: the RG35XX SP uses the BEANS build; the RG35XX Plus uses the BANANA build. These are not interchangeable.
Knulli: Download from github.com/knulli-cfw/distribution/releases. Knulli uses per-device images as well, so select the image matching your exact model. Verification is via the GitHub release checksums.
Step 2: Prepare the SD card
Neither firmware requires you to pre-format the SD card manually. The image file contains its own partition layout and will overwrite whatever is on the card.
If you’re using two cards (recommended for muOS, optional for Knulli), the second card for games should be formatted exFAT so it can be read by both firmware and your PC without extra software. Format it before first boot — muOS will detect it and set up the folder structure automatically on first launch.
Step 3: Flash the image
Open balenaEtcher (or Rufus on Windows in DD mode). Select the downloaded .img or .img.gz file. Select your SD card. Flash.
Both firmware images are single-file flashes — no manual partition resizing, no command-line steps required. Etcher typically takes 5–15 minutes depending on your card speed and image size.
Step 4: First boot
muOS first boot: The device will prompt you to confirm the device type and set the date and time manually. There is no wizard beyond this. You’ll land at the muOS home screen within about 60–90 seconds. If you inserted a second games card, muOS will populate the expected ROM folder structure on it during this first boot sequence.
Knulli first boot: EmulationStation will launch after a slightly longer initial setup phase while it configures itself. If your game card is already inserted and formatted, Knulli will scan for ROMs automatically. The EmulationStation interface will be recognisable to anyone who has used Batocera or RetroPie.
Both firmwares configure your WiFi under Settings and will detect the RG35XX SP’s hinge on Knulli (closing the lid triggers sleep). On muOS, sleep mode is supported but the hinge-to-sleep integration is a Knulli-specific feature per its fact sheet.
Step 5: Add your games
muOS
ROM folders live on the second SD card under /ROMS/. Subfolders follow RetroArch platform naming conventions — muOS creates them for you on first boot. Drop your BIOS files into /BIOS/ on the same card. muOS will pick up any new ROMs on the next manual or automatic library refresh.
Knulli
Knulli follows Batocera’s folder naming convention since it’s a Batocera fork. ROMs go into /userdata/roms/[system]/. BIOS files go into /userdata/bios/. You can transfer files over WiFi via Samba share, which Knulli enables by default when connected to a network — no card removal needed.
Common issues and fixes
WiFi drops on Knulli: Both firmwares support 2.4/5 GHz WiFi (the H700 hardware includes 802.11 a/b/g/n/ac). If you’re seeing drops specifically on 5 GHz, try forcing 2.4 GHz in your router settings for the device — community reports indicate mixed reliability on 5 GHz for the RG35XX family across firmwares.
PortMaster not available on muOS: This is not a bug. PortMaster support is a Knulli feature, not a muOS feature per its current spec sheet. If native Linux game ports (Stardew Valley, Celeste, DOOM) matter to you, this is a genuine reason to pick Knulli.
OTA updates on muOS: muOS does not list OTA updates as a supported feature. Updates require reflashing or manual package installation. Knulli supports OTA updates via the Updates & Downloads menu.
Performance tips
Both firmwares run on identical hardware — the Allwinner H700 with 1 GB LPDDR4 RAM. No firmware choice will make N64 or Dreamcast emulation dramatically better or worse; the hardware ceiling is the same either way.
Overclocking: Both muOS and Knulli list overclocking as a supported feature. The H700 is a conservative chip by default, and a modest CPU bump can improve N64 and Dreamcast frame consistency. Neither firmware’s fact sheet specifies exact clock ceilings, so treat community-posted values as indicative rather than guaranteed.
RetroAchievements: Both firmwares support RetroAchievements natively. Set up your account credentials under the RetroAchievements section of the respective settings menu. You’ll need an active WiFi connection during gameplay for achievement submission.
Theming: If visual customisation matters, Knulli has access to the broader Batocera theme ecosystem — a meaningful library advantage. muOS has its own active theme community, but it’s smaller.
The actual decision
| Feature | muOS | Knulli |
|---|---|---|
| Target hardware | Anbernic only | Anbernic + Trimui Smart Pro |
| Interface style | Custom clean UI | EmulationStation (Batocera-style) |
| PortMaster | No | Yes |
| OTA updates | No | Yes |
| Overclocking | Yes | Yes |
| RetroAchievements | Yes | Yes |
| Sleep mode | Yes | Yes |
| RG35XX SP hinge-to-sleep | Not listed | Yes |
| Beginner difficulty | Beginner | Beginner |
| Two-card setup | Strongly recommended | Supported |
Pick muOS if: You want the most widely documented, community-supported firmware for Anbernic H700 devices, you’re comfortable without game ports, and you prefer a purpose-built UI over the EmulationStation paradigm.
Pick Knulli if: You want PortMaster, OTA updates without reflashing, the RG35XX SP hinge-to-sleep behaviour, or you also own a Trimui Smart Pro and want consistent firmware across devices.
Both are stable, actively developed, and free. If you genuinely can’t decide, flash muOS first — it has the larger community knowledge base, which makes troubleshooting easier when you’re starting out. You can always switch.