// GB350 & SF3000 Family · iCube / cubegm Firmware //

R36SX
Owner's Hub

The definitive resource for R36SX / GB350 / SF3000 owners.
Tools · Guides · News — all in one place.

iCube Firmware
cubegm OS
MIPS SoC
640×480 IPS
Stock OS only (2026)
Setup Guide Get the Tools
⚡ LATEST
No custom firmware for GB350/SF3000 as of April 2026 LiamJ74 updated R36S V2.6 Wiki & Tools — sync_sd_card + download_covers scripts R36SX Stock OS backup H.OS V1.2 now available on Reddit SF3000 fully reverse engineered — full code execution achieved via MIPS32 binary PS1 compatibility spreadsheet published by community No custom firmware for GB350/SF3000 as of April 2026 LiamJ74 updated R36S V2.6 Wiki & Tools — sync_sd_card + download_covers scripts R36SX Stock OS backup H.OS V1.2 now available on Reddit SF3000 fully reverse engineered — full code execution achieved via MIPS32 binary PS1 compatibility spreadsheet published by community

News & Updates

What's Happening

Latest community discoveries, tool releases, and important notices for GB350 / SF3000 / R36SX owners.

Apr 16, 2026Important
Still No Custom Firmware for GB350 Clones
As of April 2026 there is no known working CFW (ArkOS, JELOS, EmuELEC) for the GB350/SF3000/R36SX hardware. The MIPS SoC is fundamentally different from the ARM-based genuine R36S. Community tools can dramatically improve the stock experience though.
Handhelds Wiki
Mar 2026Tool Release
R36S V2.6 Wiki & Scripts by LiamJ74
The definitive GB350/R36S V2.6 Wiki on GitHub. Includes sync_sd_card.ps1/.py to rebuild game lists and download_covers.ps1 to auto-scrape cover art. These are the tools featured in the YouTube guide video.
View on GitHub
Feb 2026Resource
R36SX Stock OS Backup (H.OS V1.2) Shared
A community member uploaded a clean stock OS image for the R36SX, which uses the same H.OS V1.2 as GB350/SF3000. Essential if your SD card gets corrupted. Download and keep a copy before touching anything.
Reddit download
2025Research
SF3000 Fully Reverse Engineered
Developer goph-R achieved full code execution on the SF3000 by replacing the cubegm launcher binary with a custom MIPS32 static binary. The rootfs and kernel have been fully mapped. Foundation for potential future CFW.
SF3000-RE on GitHub
Mar 2026Guide
R36SX: New SD Card Setup & Add Games
Detailed community guide with photos for setting up a fresh SD card on the R36SX. Covers formatting, ROM folder structure, fixing the game list, and getting cover art working with the LiamJ74 scripts.
Read on Reddit
2026Resource
PS1 Compatibility Spreadsheet Published
Community-maintained spreadsheet tracking which PS1 games work on GB350/V2.6 hardware. Hundreds of games tested and rated. Critical resource before filling your card with PlayStation ROMs.
View spreadsheet

Hardware

Device Specifications

The GB350, SF3000, and R36SX share the same MIPS-based hardware and iCube/cubegm firmware. They are NOT the same as the genuine ARM-based R36S.

Processing

ArchitectureMIPS32 (NOT ARM)
SoCMIPS-based (Ingenic family)
RAM~128–256 MB
GPUNone (no SDL/EGL/GLES)
Framebuffer/dev/fb0 via DirectFB

Display & Screen

GB350 Screen3.5″ IPS
SF3000 Screen4.5″ IPS
Resolution640 × 480
Cover Art320 × 240 PNG
BG Raw Format640 × 480 BGRA

Firmware / OS

OS BaseBuildroot Linux
LauncheriCube / cubegm
Stock VersionH.OS V1.2 (R36SX)
CFW AvailableNone (as of Apr 2026)
Core LibsMIPS32 .so objects

Storage & I/O

SD SlotSingle MicroSD
FormatFAT32 / exFAT
Max Tested256 GB
ChargingUSB-C (charge only)
WiFi / BTNone on stock

Setup Guide

Fresh SD Card Setup

How to set up a new SD card, add games, and get cover art working — from scratch. Based on the video guide.

⚠️
No CFW exists for this device yet (April 2026)

Unlike the genuine R36S (ARM Cortex), your GB350/SF3000/R36SX runs a MIPS SoC. ArkOS, JELOS, and EmuELEC are ARM-only and WILL corrupt your card if flashed. This guide covers everything possible with the stock iCube/cubegm OS. Track CFW progress at handhelds.wiki.

⚠ Do This First
Backup Your Stock SD Card

Use Win32DiskImager (Windows) or dd (Linux/Mac) to clone your original card to a .img file. If your card breaks later, you can restore it. The community R36SX stock OS backup (H.OS V1.2) is also on Reddit if you need to start fresh.

Step 2
Understand the SD Structure

Your SD card has a cubegm/ folder (firmware + settings + game lists) and one folder per platform: GBA/, FC/, SFC/, PS/, MD/, etc. Each platform folder holds ROMs, a filelist.csv index, and an images/ subfolder for cover art.

Step 3
Add Your ROM Files

Copy ROMs into the correct platform folder. Extensions must match what cubegm/cores/config.xml maps to each emulator core. Avoid commas in filenames — the sync script will fix those automatically. Don't put ROMs in random folders.

Step 4
Rebuild Game Lists with sync_sd_card

After adding ROMs, run sync_sd_card.ps1 (PowerShell) or sync_sd_card.py (Python). Always dry-run first to preview, then add -DryRun $false to apply. Rebuilds allfiles.lst + all filelist.csv files.

Step 5
Scrape Cover Art with download_covers

Run download_covers.ps1 pointing at your SD drive letter. Auto-fetches and saves as 320×240 PNG in each platform's images/ folder. Oversized images silently break thumbnails — the script resizes automatically.

Step 6 (Optional)
Edit the Theme

cubegm/UI_Res.cpd is a renamed ZIP archive. Open with any ZIP tool, swap the 640×480 BGRA raw background images, repack. Use the web-based gb300-sf2000-tool for a GUI editor.

Done
Eject Safely & Boot

Always safely eject before removing the card. First boot after adding games may be slower. If games still don't appear, re-check that filelist.csv was rebuilt by the sync script. If device won't boot, re-flash the stock backup.


Reference

SD Card File Structure

Know this layout before making any changes to your SD card.

Root of SD Card (H:\)
H:\
├── cubegm/                    # Firmware & launcher environment
│   ├── rkgame                 # Main menu binary (MIPS32)
│   ├── icube_start.sh         # Edit to run custom code first
│   ├── UI_Res.cpd             # Theme assets (renamed ZIP of 640×480 BGRA raws)
│   ├── resource.cpd           # Core UI layout ZIP
│   ├── setting.xml            # User settings (language, volume, hotkeys)
│   ├── allfiles.lst           # Master game index — rebuilt by sync_sd_card
│   ├── favorites.lst / recent.lst
│   ├── cores/
│   │   ├── config.xml         # Maps file extensions → emulator cores
│   │   └── filelist.xml       # Per-game core overrides
│   ├── saves/                 # Save files
│   ├── states/                # Save states (PLATFORM/romname)
│   └── lib/                   # BIOS files go here
├── GBA/                       # One folder per platform
│   ├── MyGame.gba
│   ├── filelist.csv           # Game list rebuilt by sync_sd_card
│   └── images/                # Cover art — 320×240 PNG per ROM
├── FC/    # NES/Famicom
├── SFC/   # Super Nintendo
├── PS/    # PlayStation 1
├── GBC/   # Game Boy Color
├── GB/    # Game Boy
├── MD/    # Sega Genesis/Mega Drive
└── ARCADE/ # Arcade (MAME subset)

Community Tools

Essential Tools

The tools from the video guide and the best community resources for GB350 / SF3000 / R36SX owners.

🖼️
Image Scraper
Auto-downloads cover art for all your ROMs and saves them as 320×240 PNG in the correct images/ folders. Handles resizing — oversized images silently break thumbnails.
PowerShellPython
download_covers.ps1 →
🔄
Game List Updater
Rebuilds allfiles.lst and all filelist.csv files from your actual ROMs. Run after adding, removing, or renaming any games. Also fixes filenames with commas.
PowerShellPython
sync_sd_card.ps1 →
🎨
Theme Editor
Platform backgrounds and icons are packed in UI_Res.cpd (renamed ZIP). Open it, swap 640×480 BGRA raw images, repack. The gb300-sf2000-tool also has a GUI editor for this firmware family.
Web AppWindows
gb300-sf2000-tool →
💾
Stock OS Backup
Clean H.OS V1.2 backup for the R36SX. If your card gets corrupted or you need a clean start, flash this with Win32DiskImager or Balena Etcher. Keep a copy locally before touching anything.
Win32DiskImagerBalena Etcher
Download Backup →
📖
Full Wiki (LiamJ74)
Complete docs for R36S V2.6 / GB350 / SF3000: cubegm file formats, emulator core mapping, save state system, background customization, troubleshooting. The best single reference for this platform.
GitHub Wiki
View Full Wiki →
🔬
SF3000 Reverse Eng.
Complete RE of the SF3000 by goph-R. rootfs, kernel, cubegm, and core binaries all mapped. Full code execution via MIPS32 binary replacement. Foundation for any future CFW development.
Research
SF3000-RE →

Emulation

Game Compatibility

Performance on stock iCube/cubegm MIPS firmware. Much weaker than ARM devices — no 3D system support.

SystemCorePerformanceStatus
Game Boy / GBC
GB / GBC folder
gambatte
100%
Perfect
Game Boy Advance
GBA folder
mGBA
100%
Perfect
NES / Famicom
FC folder
FCEUmm
100%
Perfect
Super Nintendo
SFC folder
Snes9x
~85%
Great
Sega Genesis / MD
MD folder
PicoDrive
100%
Perfect
PlayStation 1
PS folder — check spreadsheet
PCSX-ReARMed
~65%
Varies
Arcade (MAME)
ARCADE folder
MAME subset
~45%
Simple games only
N64 / Saturn / PSP
3D systems
N/A
~5%
Not supported

FAQ

Frequently Asked Questions

Common questions from R36SX, GB350, and SF3000 owners.

Is my R36SX the same as a GB350 or SF3000?
Yes. R36SX, GB350, SF3000, R36S V2.5/V2.6/V2.7, R36HD and others are all names for clones sharing the same MIPS-based hardware and iCube/cubegm firmware. They differ only cosmetically. Any tool or guide for one works on all of them.
Can I install ArkOS, JELOS, or EmuELEC?
No. As of April 2026 there is no working CFW for GB350/SF3000. These devices run a MIPS32 SoC, while ArkOS/JELOS/EmuELEC are ARM-only. Flashing ARM images WILL corrupt your SD card. Watch handhelds.wiki for any CFW updates.
My games aren't showing up after I added ROMs.
The firmware doesn't auto-detect new ROMs. Run sync_sd_card.ps1 or sync_sd_card.py from LiamJ74's GitHub to rebuild allfiles.lst and filelist.csv. Always dry-run first to preview, then apply with -DryRun $false.
Cover art isn't showing / thumbnails are broken.
The firmware strictly requires 320×240 PNG. Wrong size or format silently fails. Use download_covers.ps1 — it auto-fetches and resizes. Manually check: image must be named exactly after the ROM (no extension) and placed in the images/ subfolder inside the correct platform folder.
How do I edit the theme / change backgrounds?
cubegm/UI_Res.cpd is a ZIP archive with a renamed extension. Open with any ZIP tool, replace the 640×480 BGRA raw background files, and repack. You can also use the web-based gb300-sf2000-tool which has a GUI theme editor.
My save states disappeared after renaming a ROM.
Save states are stored in cubegm/states/PLATFORM/ named after the ROM filename. Renaming a ROM breaks the link. Rename the save state files in that folder to match the new ROM name. Avoid renaming ROMs after you've made saves.
PS1 games not working — what BIOS do I need?
Place PS1 BIOS files in cubegm/lib/. You need: scph1001.bin, scph5500.bin, scph5501.bin, scph5502.bin. Not all PS1 games work well — check the community PS1 compatibility spreadsheet first.
SD card corrupted / device won't boot. Help?
Flash the stock H.OS V1.2 backup from this Reddit post to a new SD card using Win32DiskImager or Balena Etcher. Use a quality Class 10 / A1 rated card to prevent future corruption.