Anbernic RG35XX SP Review: The Clamshell Done Right

The RG35XX SP is Anbernic’s explicit tribute to the Game Boy Advance SP — same clamshell hinge, same portrait-ish proportions, same “flip it open and play” ritual. It launched in May 2024 running an Allwinner H700 SoC, and it slots into a crowded family of H700-based devices from Anbernic. What sets it apart from the Plus and the H is the form factor: the clamshell protects the screen when you throw it in a bag, which sounds minor until you’ve scratched a flat device.

This is a GBA-through-PS1 machine. It does those things well. If you’re chasing PSP or need analog sticks for N64, close this tab and look at the RG40XX H or the Retroid Pocket 4. For everything else, the SP is a compact, well-built device with strong custom firmware support.

Hardware and build quality

The SP weighs 192 g and closes to 89 × 85 × 27 mm — it’s genuinely pocketable in a jacket or cargo pocket, not a jeans-front-pocket device. That weight feels solid rather than heavy; there’s no flex in the hinge or the shell under normal use.

The clamshell hinge is the defining physical feature, and it earns its reputation. The screen folds completely flat against the back of the device, which means you can toss this in a bag without a case and not worry. Reviewers consistently describe it as satisfying to open and close, which matters more than it sounds after several weeks of daily use.

Controls are a mixed story. The D-pad is a raised crosspad that community reviewers describe as crisp — it’s genuinely good for 2D action games and fighting titles. The ABXY face buttons are tactile. Shoulder buttons are L1/R1 (tactile) and L2/R2, though the SP’s clamshell geometry limits the surface area available for shoulder grips, so extended play with L2/R2 is less comfortable than on a flat device. There are no analog sticks — zero — which is a hard constraint you need to accept before buying.

The speaker is mono, and reviews describe it as functional rather than impressive. Using headphones via the 3.5 mm jack is the better path for anything with a real soundtrack.

Connectivity includes Wi-Fi (2.4/5 GHz 802.11 a/b/g/n/ac), Bluetooth 4.2 (controllers only per manufacturer), mini HDMI out, and USB-C. That USB-C port is charging-only at 5V/1.5A — no data transfer per the manufacturer spec. Plan your ROM loading workflow around the dual microSD slots accordingly.

Screen

The 3.5-inch IPS panel runs at 640×480 with OCA full lamination. The 4:3 aspect ratio is the right call for this class of device: Game Boy, SNES, PS1, and most retro systems are 4:3 native, so you’re getting pixels to the edges rather than burning screen real estate on letterboxing.

GBA games run at 240×160, which is a 3:2 aspect — you’ll get thin black bars on the sides at native resolution on this 4:3 panel. That’s consistent with every 4:3 device in this class; it’s not a flaw, just physics. Integer scaling looks clean.

Full lamination (OCA) means the glass sits flush against the panel with no air gap, which reduces internal reflections and improves perceived contrast. The practical difference is visible in moderate ambient light — there’s less of the “screen inside a fishbowl” look you get from non-laminated panels. For a device in this price bracket, it’s a feature worth calling out.

Performance

The RG35XX SP runs a quad-core ARM Cortex-A53 at 1.5 GHz (Allwinner H700) with a Mali-G31 MP2 GPU and 1 GB LPDDR4 RAM. This is the same silicon as the RG35XX Plus and RG35XX H — you’re buying the clamshell form factor, not a performance upgrade.

The H700 is a well-understood chip at this point. GBA and PS1 run flawlessly. N64 and Dreamcast are playable with caveats. PSP is marginal.

GBA is fully solved on this hardware — mGBA at full speed, no compromises, native resolution fits the 4:3 panel well. PS1 is the same story: the full tested library runs at full speed via PCSX ReARMed. These two platforms alone justify the purchase for a large portion of the retro library.

N64 is playable, but the lack of analog sticks is the real problem, not the SoC. Even when a game runs at a playable framerate, anything designed around an analog stick — Mario 64, Ocarina of Time — is functionally compromised with D-pad mapping. The N64’s demanding emulation characteristics also mean compatibility is game-specific; lighter titles fare better than heavier ones like GoldenEye or Perfect Dark.

Dreamcast runs most of the library at a playable framerate via Flycast — community sources describe the SP as “capable of handling up to DS, N64, and Dreamcast.” Heavier titles may need frameskip. PSP is where the H700 hits a wall: retrohandhelds.gg describes it as “not really something we’d recommend” on this hardware. Lighter PSP titles at 1x resolution may run acceptably, but don’t buy an SP expecting a PSP library.

Battery life

The SP carries a 3300 mAh battery. Anbernic’s manufacturer claim is 8 hours. Community reviews did not conduct controlled timing tests, so treat the 8-hour figure as the optimistic ceiling — real-world numbers under emulation load will vary by firmware, display brightness, and Wi-Fi usage. The form factor means the battery sits in a clamshell chassis, and closing the lid to sleep (especially on Knulli, which has explicit hinge support) helps preserve charge during breaks.

Firmware and software

The stock OS is Anbernic’s 64-bit Linux launcher. It works, but most users replace it within the first week. The SP officially supports two custom firmware projects: muOS and Knulli. MinUI also runs unofficially.

muOS (MustardOS)

muOS is the most mainstream custom firmware for H700-class Anbernic devices and is generally regarded as the most beginner-friendly option. On the RG35XX SP specifically, the build codename is BEANS — distinct from the BANANA build used on the RG35XX Plus and H. That distinction matters at install time: flashing the wrong build is a recoverable mistake but a frustrating one. Installation is an SD card flash with balenaEtcher or Rufus, estimated at around 30 minutes, and is reversible via stock firmware reflash.

muOS includes RetroArch integration, RetroAchievements support, theme support, overclocking, and netplay. The recommended setup uses two SD cards — one for the OS, one for ROMs — which the SP’s dual-slot layout supports cleanly.

Knulli

Knulli is a fork of Batocera Linux, created specifically because Batocera’s GPL license is incompatible with the closed-source GPU and display drivers required on H700 hardware. It uses an EmulationStation-style frontend (familiar to anyone coming from Batocera), and includes several features muOS lacks by default: PortMaster support (enabling native Linux ports like Stardew Valley, Celeste, and DOOM), OTA updates, and — notably for this device — explicit hinge support. On Knulli, closing the SP’s lid triggers sleep mode. That’s a small quality-of-life feature that makes the clamshell feel like a first-class citizen rather than an afterthought.

Knulli also supports RetroAchievements and netplay. The theme ecosystem draws from the broader Batocera pool.

MinUI

MinUI runs unofficially on the SP. If you want a minimal, no-frills interface and are comfortable with an unsupported setup, it’s an option — but expect to do more manual configuration compared to muOS or Knulli.

Pros and cons

Verdict

The RG35XX SP is the best argument for buying a clamshell retro handheld at this price point. If your emulation diet is GBA, SNES, Mega Drive, Neo Geo, and PS1 — with occasional Dreamcast and DS in the mix — the SP covers all of it with a screen and build quality that hold up to daily use. The Knulli firmware in particular makes it feel polished: hinge-to-sleep works, PortMaster expands the software library, and OTA updates mean you’re not flashing SD cards every time there’s a fix.

Skip it if analog sticks are non-negotiable. The no-stick constraint isn’t just about N64 — it affects PSP navigation menus, certain DS titles, and anything that assumed two analog axes as a baseline. The RG40XX H shares the same SoC but adds analog sticks for a different use case. If the clamshell form factor appeals but you want more emulation headroom, that’s the direction to look. For the pocket-sized GBA-through-PS1 use case with excellent CFW support, the SP at $64.99 is hard to argue against.