R36S Custom Firmware Guide — Best CFW Options (2025)

The R36S handheld game console ships with a basic version of ArkOS, but installing custom firmware (CFW) dramatically improves performance, adds features, and unlocks the full potential of this budget retro gaming device. In this guide, we cover every R36S firmware option available in 2025, with step-by-step installation instructions and honest comparisons.

🎮 What is Custom Firmware?
Custom firmware (CFW) replaces the operating system on your R36S with a community-developed alternative. It improves emulator performance, adds new features, and fixes bugs that exist in the stock firmware. Think of it as upgrading your phone's operating system to the latest version — everything works better.

📑 Table of Contents

🔧 Before You Start — What You Need

Before flashing any custom firmware to your R36S, make sure you have the following ready:

  • A quality microSD card (at least 32GB, Class 10 or UHS-I). The stock SD cards that ship with the R36S are notorious for failing — we strongly recommend replacing them with a reputable brand like SanDisk or Samsung.
  • A microSD card reader for your computer.
  • Balena Etcher (free) or Win32 Disk Imager — software to flash firmware images to SD cards.
  • A computer running Windows, macOS, or Linux.
  • The correct firmware image for your R36S screen panel version (see below).
⚠️ Important: Replace your stock SD cards! The microSD cards that come with the R36S are cheap and prone to data corruption. Investing $10-15 in a quality card will save you from losing your save files and game data.

🔍 How to Check Your R36S Screen Panel Version

The R36S comes with different screen panel versions, and choosing the correct firmware image depends on which panel your device has. Here's how to check:

Method 1: Boot Text Check

  1. Power on your R36S while watching the boot screen closely.
  2. Look for text that reads either "R36S V1", "R36S V2", or similar during the initial boot.
  3. Note which version is displayed — this determines which firmware image you need.

Method 2: Physical Inspection

  1. The original R36S has a slightly different screen bezel and display characteristics.
  2. Clones and revised models may display slightly different colour temperatures or brightness levels.
  3. When in doubt, try the standard image first — if it doesn't display properly, try the alternative version.

📊 R36S Firmware Comparison Table

Firmware Status Frontend Key Strengths Difficulty
ArkOS Active EmulationStation Most Compatible, Fast Boot, Regular Updates Easy
ROCKNIX Recommended EmulationStation Best UI, Simplified Settings, Active Development Easy
JELOS Discontinued EmulationStation Stable, Built-in Config Menus Easy
AmberElec Discontinued EmulationStation Lightweight, Simple Easy
MyMinUI Active MinUI (Minimal) Ultra-Clean Interface, Fast Medium

🟢 ArkOS — The Default Choice, Upgraded

ArkOS is the firmware that ships on the R36S, but the version that comes preinstalled is typically outdated. The latest version of ArkOS includes significant performance improvements, better emulator cores, and bug fixes that make it well worth updating.

ArkOS uses the EmulationStation frontend — a clean, user-friendly interface that organises games by system (NES, SNES, PlayStation, etc.) — combined with RetroArch cores for emulation.

Key Features of ArkOS

  • ✅ Regular updates with latest emulator improvements
  • ✅ Fast boot time (~15 seconds)
  • ✅ RetroArch + standalone emulator support
  • ✅ Save state and save file support
  • ✅ Custom themes available
  • ✅ Wi-Fi file transfer support (on Wi-Fi enabled models)
  • ✅ Extensive game compatibility

How to Update ArkOS on the R36S

There are two methods to get the latest ArkOS on your R36S:

Method 1: Official ArkOS Image + R36S DTB Patch

  1. Download the RG351MP version of ArkOS from the official ArkOS GitHub wiki.
  2. Download the R36S-specific DTB file: rk3326-rg351mp-linux.dtb
  3. Flash the ArkOS image to a fresh microSD card using Balena Etcher.
  4. After flashing, open the Boot partition on your computer.
  5. Replace the existing DTB file with the R36S-specific one you downloaded.
  6. Insert the SD card into the TF-OS slot of your R36S and power on.

Method 2: Community R36S ArkOS Image (Easier)

Community member AeolusUX maintains a pre-patched ArkOS image specifically for the R36S. No DTB replacement needed — just flash and boot!

  1. Download the latest release from AeolusUX/ArkOS-R3XS GitHub.
  2. Flash the image to a fresh microSD card using Balena Etcher.
  3. Insert the SD card into the TF-OS slot and power on.
  4. Done! ArkOS will boot and configure itself on first run.
💡 Tip: Method 2 is the easiest and most reliable way to get the latest ArkOS running on your R36S. We recommend this approach for beginners.

🔵 ROCKNIX — Best Alternative Firmware

ROCKNIX is a continuation of the JELOS custom firmware under a new name. When some of the original JELOS developers stepped away, the remaining team rebranded and continued active development under the ROCKNIX name.

In our experience, ROCKNIX is the best alternative to ArkOS for the R36S. It brings simplified configuration directly into the frontend menu, making it incredibly easy to tweak emulator settings without diving into RetroArch menus.

Key Features of ROCKNIX

  • ✅ Active, ongoing development with regular updates
  • ✅ Simplified settings — access everything by pressing the Start button
  • ✅ Per-game configuration options accessible from the game list
  • ✅ EmulationStation frontend with modern themes
  • ✅ RetroArch + standalone emulator cores
  • ✅ Built-in scraping for game artwork
  • ✅ FTP file transfer for easy ROM management over Wi-Fi
  • ✅ More stable and tidier experience than stock ArkOS

How to Install ROCKNIX on the R36S

  1. Visit the ROCKNIX GitHub releases page.
  2. Download the R36S version of the firmware image (look for "R36S" or "RK3326" in the filename).
  3. Flash the image to a fresh microSD card using Balena Etcher.
  4. Insert the SD card into the TF-OS slot (the top slot) on your R36S.
  5. Power on the device — ROCKNIX will initialise and expand the storage partition on first boot.
  6. First boot may take 1-2 minutes. Be patient and don't turn it off during this process.
  7. Once booted, you can add ROMs via USB, SD card reader, or FTP if Wi-Fi is available.
🎮 Why We Love ROCKNIX: The ability to press Start on any game and instantly see/change the emulator settings is a game-changer. No more digging through RetroArch menus to change screen ratios, shaders, or input mappings.

🟣 JELOS — The Foundation

JELOS (Just Enough Linux OS) was one of the most popular custom firmware options for retro handhelds. It was very similar to ArkOS in using the EmulationStation frontend, but distinguished itself with an in-menu configuration system that made tweaking settings far more intuitive.

⚠️ Note: JELOS has been discontinued. The developers have moved to ROCKNIX, which is essentially JELOS under a new name with continued updates. We recommend using ROCKNIX instead.

If you still want to try JELOS, you can download the last release from the JELOS GitHub.

💡 Important: After installing JELOS on the R36S, press the Start button, navigate to System Settings, and enable the "Device is R36S/R35S?" option for full compatibility.

🟠 AmberElec — Legacy Option

AmberElec was originally developed for the Anbernic RG351 line of devices. Since the R36S uses the same RK3326 chipset, AmberElec is compatible — but it's not officially supported for the R36S.

Like JELOS, AmberElec is no longer actively developed. This means it won't receive the latest emulator performance improvements for systems like N64, Dreamcast, or PSP.

If you still want to try it, download the RG351MP version from amberelec.org.

🔮 Other CFW Options

MyMinUI

A minimalistic alternative to EmulationStation that can be installed on top of ArkOS. If you prefer aa clean, stripped-down interface without all the bells and whistles, MyMinUI is worth exploring. It focuses on launching games quickly with minimal distractions.

dArkOSRE

A community fork of ArkOS with additional features and support for multiple R36S hardware versions. It includes extra customisation options and community-developed patches.

Multiboot Images

Can't decide? Multiboot images are available that let you install multiple operating systems on a single SD card. On boot, you choose which firmware to load — perfect for testing different options.

🏆 Which Firmware Should I Choose?

If you want... Choose this
The easiest upgrade from stock ArkOS (Community Image)
The best overall experience ROCKNIX ⭐
The most customisation options ArkOS
A minimal, distraction-free experience MyMinUI
To try everything Multiboot Image
Our Recommendation: For most R36S users, we recommend starting with ROCKNIX. It offers the best balance of performance, ease of use, and active development. If you're already comfortable with the stock ArkOS and just want improvements, update to the community-maintained ArkOS image.

📝 Step-by-Step: How to Flash Custom Firmware

This process is the same regardless of which firmware you choose:

Step 1: Download the Firmware

Download the correct firmware image for your R36S from the links provided above. Make sure you select the right version for your screen panel.

Step 2: Download Balena Etcher

Get Balena Etcher (free, available for Windows, macOS, and Linux). This is the safest and easiest tool for flashing firmware images.

Step 3: Insert Your microSD Card

Insert a fresh, quality microSD card into your card reader and connect it to your computer. Important: All data on this card will be erased!

Step 4: Flash the Image

  1. Open Balena Etcher.
  2. Click "Flash from file" and select the firmware image you downloaded.
  3. Click "Select target" and choose your microSD card.
  4. Click "Flash!" and wait for the process to complete (usually 5-15 minutes).

Step 5: Insert and Boot

  1. Safely eject the SD card from your computer.
  2. Insert it into the top TF-OS slot of your R36S.
  3. Power on the device.
  4. The first boot may take 1-3 minutes as the system configures itself.

Step 6: Add Your ROMs

After the initial setup, power off the R36S. Remove the SD card and insert it back into your computer. You'll see a ROMS folder (or similar) — copy your game files into the appropriate system folders (e.g., /ROMS/NES/, /ROMS/SNES/, /ROMS/PSX/).

🔧 Troubleshooting Common Issues

Black screen after flashing

  • Make sure you downloaded the correct version for your screen panel.
  • Try a different microSD card — cheap cards are often the cause.
  • Re-flash the image and ensure the process completed without errors.

Distorted or garbled display

  • This usually means you have the wrong screen panel version. Try the alternative firmware image.
  • For ArkOS, ensure you replaced the DTB file with the correct R36S version.

Games not appearing in the menu

  • Ensure your ROM files are in the correct folders.
  • Try rebooting the device — the game list updates on startup.
  • Check that your files are in supported formats (e.g., .nes, .sfc, .bin/.cue for PSX).

SD card corruption / data loss

  • Replace the stock SD cards immediately. Use a brand-name card (SanDisk, Samsung, Kingston).
  • Always safely eject the SD card from your computer before removing it.
  • Back up your save files regularly.

Poor performance on certain games

  • Update to the latest firmware version — emulator performance improves with each release.
  • Some demanding systems (N64, PSP, Dreamcast) may require per-game configuration tweaks.
  • Try different emulator cores — in the game settings, you can usually switch between multiple options.

❓ Frequently Asked Questions

Will installing custom firmware void my warranty?

Custom firmware is a software change that is completely reversible. You can always flash the stock firmware back to restore the original state. Since the R36S ships with open-source Linux-based firmware, the community firmware options are built on the same foundations.

Will I lose my games when switching firmware?

Yes, flashing custom firmware to a new SD card means you'll need to copy your ROM files to the new card. However, we recommend this approach as it gives you a clean installation. You can keep your old SD card as a backup.

Can I dual-boot different firmware?

Yes! Multiboot images are available that let you choose between different firmware options on startup. Alternatively, you can keep different firmware on separate SD cards and simply swap them.

How often should I update my firmware?

We recommend checking for updates every 1-2 months. ArkOS and ROCKNIX both receive regular updates that improve emulation performance and add new features.

Which firmware has the best N64/PSP performance?

Both ArkOS and ROCKNIX use the latest emulator cores and offer similar N64/PSP performance. The RK3326 chip in the R36S can handle most N64 and many PSP games, though some more demanding titles may require frame skipping or lower resolution settings.

Do I need Wi-Fi for custom firmware?

No. Wi-Fi is optional and only needed for features like firmware updates over the air, ROM transfer via FTP, and game artwork scraping. All core gaming features work perfectly offline.

Is it hard to install custom firmware?

Not at all! The process is essentially: download the image, flash it to an SD card, insert it, and boot. It takes about 15-20 minutes total, and the tools (like Balena Etcher) have user-friendly interfaces that guide you through each step.

🎮 Ready to upgrade your R36S?

Get the R36S handheld console and start your retro gaming adventure today.

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