Anbernic RG35XX Family Starter Guide

Last updated: 26OCT2024 (see Changelog for details)

Anbernic’s budget line of devices, using the Allwinner H700 CPU, are an excellent combination of affordability and performance. This guide will help you get started with this entire family of handheld emulation devices, which includes:

Anbernic RG35XX Plus
Anbernic RG35XX “2024”
Anbernic RG35XX H
Anbernic RG35XX SP
Anbernic RG28XX
Anbernic RG40XX H
Anbernic RG40XXV
Anbernic RG Cube XX

Note: if you’re looking for the original Anbernic RG35XX, that guide is right here.

Table of Contents

Choose a handheld
Where to buy
Charging and safety
Recommended accessories
ROMs and BIOS
Choose an operating system
Stock (Anbernic) OS
Modded stock OS
Recommended stock OS tweaks
KNULLI
muOS
MinUI
GarlicOS 2.0
ROCKNIX
Shaders, overlays, and more
Hardware mods

Changelog

Choose a handheld

One of the best things about the RG35XX family of devices is that it seems like there is an option for everyone. Want something that reminds you of a Game Boy? RG35XX Plus. Clamshell and clicky buttons? Easy, the SP. Ultra pocketable? RG28XX. I personally like the RG35XX H the best, because I find it the most comfortable thanks to its horizontal layout, and it has stereo speakers and dual analog sticks.

Below you will find my videos on each handheld, including first impressions and a more detailed review. Each of the devices are capable of HDMI out, but keep in mind that the RG28XX and RG35XX “2024” models do not have WiFi or Bluetooth.

Anbernic RG35XX Plus — Impressions // Review
Anbernic RG35XX “2024” — Review
Anbernic RG35XX H — Impressions // Review
Anbernic RG35XX SP — Impressions // Review
Anbernic RG28XX — Review
Anbernic RG40XX H — Impressions // Review
Anbernic RG40XXV — Review
Anbernic RG Cube XX — Review

Where to buy

The Anbernic RG35XX family of devices are widely available, from a variety of sources.

3.5″ devices:

2.8″ and 4.0″ devices:

AliExpress: If you want the best deal, I recommend shopping around on AliExpress, and waiting for site-wide sales to maximize your value. Buying directly from Anbernic’s AliExpress store will usually give you a fair price, but there are other dropshipping stores like Cutesliving and Ampown who will undercut the price to give you an even better deal. Note that because they are shipping from China, it will generally take a couple weeks to arrive.

Anbernic: You can also buy the devices directly from Anbernic. Depending on how long the device has been available, they may offer shipping from warehouses in the US and Europe. These prices will generally be higher than on AliExpress, and they will charge shipping.

Dropshippers: There are third-party websites that offer Anbernic products, like KeepRetro, GoGameGeek, and LITNXT. They may offer discounts, but generally their prices will be higher than AliExpress or Anbernic directly.

Amazon: There are also vendors who sell Anbernic devices on Amazon. These prices will almost always be higher than AliExpress, but there are periodic sales that are competitive with Anbernic’s website prices and sometimes even AliExpress. The advantage of Amazon is that you have an easier return/refund process in case you get a faulty unit, and faster shipping.

Charging and safety

The RG*XX line of devices are known for being very affordable, but that also means that many of its components are rather cheap. One important example has to do with charging; there is not a consensus on the issue, but the overall sentiment is that these devices are lacking in proper voltage regulation. This means that a contemporary USB-C fast charger (like those used for modern smartphones) will likely not work on these devices, because it cannot properly regulate the signal.

There have been reports of overcharged (and even hazardous) batteries on devices, which is usually linked to the charging brick or a failed component on the device itself. This happens with other handhelds from other companies as well, and it is best to be vigilant when charging any cheap electronic device.

For the best results, I recommend using a USB-A cable (like the one that comes with your device), and a brick that meets the specific charging signal the device requires. The RG*XX devices will not come with a charging brick, but on the back of the device there is a sticker or other text that specifies the required adapter input. This will look like “5V => 1.5A” or something very similar. To make sure your device is properly charged, I would recommend using an adapter that has that exact spec, and to only charge the device under supervision (for example, don’t charge it overnight). Here is a link to a charging brick that has the exact 5V 1.5A output that most Anbernic devices require.

Recommended accessories

The RG35XX family of devices will have two microSD card slots — the first is for the operating system, and the second slot is generally used for additional game storage. Depending on the operating system you choose (more on that later), you can either use a single-card or dual-card setup. The card that comes with the device will likely be 64GB and filled with games, and depending on where you buy the device, there may be an option to buy a second card filled with more games. I recommend adding your own ROM library instead, to curate your retro gaming experience, and because the games that come on these cards are often poorly organized or are mismatched regions/languages.

While previously Anbernic had been using cheap, generic microSD cards for their devices, they have recently switched to using KIOXIA cards, which are a sub-brand of Toshiba. These cards are reliable and can generally be used in most situations. The general rule is this: if your device came with a blue KIOXIA card, it should be pretty reliable, but if you got a generic black microSD card, it will be more apt to fail (especially if you try to flash a firmware to it).

Note that some custom firmwares (like MinUI) are meant to be used ON TOP of the standard card that comes with the device, while others can be installed on brand new cards. If you have the means, I would recommend picking up a couple different cards so that you can experiment with several OS options to find the one that matches you the best.

Each OS option uses a slightly different setup: MinUI is designed to work with two different cards, while the others can all be placed on a single card if you’d like. So for MinUI, I would recommend a 16GB OS card, and another larger card for games. For Knulli or muOS, you can use a single large for both the OS and games, or a two-card setup.

In general, I recommend the cards listed below, in order or preference. The prices fluctuate all the time, so keep an eye out for deals. A 128GB card will allow you to load EVERY 8-bit and 16-bit game out there, just about all of the arcade games that work, and quite a few PS1, Dreamcast, PSP, and Sega CD games (those systems have the largest file sizes). A 256GB or 512GB card will allow you to store even more of those larger games, but is mostly overkill for devices such as these.

As far as model (“Extreme” vs “Ultra”, etc), this won’t matter when it comes to playing games. Some cards may transfer files more quickly (like when adding ROMs to the card), but the difference will be negligible. Instead, shop around for the best deal based on your desired amount of storage!

16GB cards: 
SanDisk Ultra  
SanDisk Industrial

32GB cards:
Samsung Pro Endurance
SanDisk Extreme

64GB cards:
Samsung Pro Endurance
SanDisk Extreme

128GB cards:
Samsung EVO Select
SanDisk Ultra

256GB microSD:
SanDisk Ultra
Samsung EVO Select
Samsung Pro Plus

512GB microSD:
SanDisk Ultra
Samsung EVO Select
Samsung Pro Plus

Note that when upgrading your firmware card to a new card, you cannot simply copy and paste your files onto the new card — the original card has several specific partitions that are necessary to run the system. Instead I would recommend flashing Modded Stock OS onto the new card, or a custom OS like KNULLI or muOS (all detailed later in this guide).

Additionally, these devices can double as a pseudo home console, thanks to their HDMI output function as well as the ability to connect to controllers via bluetooth or USB. The HDMI adapter is smaller than the standard size, so you will either want to grab a mini HDMI cable like this one, or a mini HDMI adapter to use with an existing cable.

If you don’t have a nice microSD to USB reader, you might want to think about getting one. A nice adapter like this one from Anker will give you fast transfer speeds, and won’t cause any corruption issues with your card. There is also a fancy new USB-C/A adapter now available!

Most RG35XX devices can also connect to Bluetooth controllers. The RG28XX and RG35XX “2024” models don’t have Bluetooth, but support controllers connected via their “USB/OTG” port. I recommend the 8bitdo SN30 Pro controllers, which are usually around $40 and can connect easily to the device.

ROMs and BIOS files

As you set up a device, it’s always best to build your own ROM library. This allows you to curate your games lists, and source them on your own. Many of these devices will come pre-loaded, but the games are often poorly organized, in the wrong language, and of shady origins. If you want to dump your own retro cartridges, I recommend the Save the Hero Builders cartridge reader, which will allow you to extract your ROM file from most popular retro systems, AND your save files at the same time. ROM and BIOS files are copyrighted, and not shared on this website. Here is a general list of game systems that you can play on the RG35XX family of devices (actual supported systems varies by OS). Those noted with an asterisk cannot play every game at full speed, and so performance may vary.

When getting ROM files, I recommend using the “No-Intro” naming convention, which is the standard naming used for ROM sets within RetroArch and other emulation communities. By using no-intro naming, you will be more likely to get box art automatically added when you load up your games and scrape their media. If you have a question as to how a game should be named, I recommend checking out the Libretro thumbnails directory. If your game name matches the thumbnail name found in this directory, chances are that it will properly download the media for it.

Additionally, an important component of a ROM library is maintaining BIOS files. BIOS files are system files necessary for some emulators (GBA, Sega CD, or PS1), and are helpful in improving accuracy with other systems. These files are copyrighted so you are on your own to find them; here is more information about BIOS files.

Here is a listing of the most common BIOS files:

GAME BOY (for boot logo):
gb_bios.bin

GAME BOY COLOR (for boot logo):
gbc_bios.bin

GAME BOY ADVANCE:
gba_bios.bin

FAMICOM DISK SYSTEM:
disksys.rom

NEO GEO:
neogeo.zip

SEGA CD:
bios_CD_E.bin
bios_CD_J.bin
bios_CD_U.bin

TURBOGRAFX-CD:
syscard1.pce
syscard2.pce
syscard3.pce

PLAYSTATION 1:
scph5501.bin
psxonpsp660.bin (MinUI)

SATURN:
saturn_bios.bin

DREAMCAST:
dc_boot.bin
naomi.zip (Naomi)
awbios.zip (Atomiswave)

The location of ROM and BIOS files on your microSD card will depend on the OS that you use. We’ll discuss each in their respective sections.

Choose an operating system

There are a variety of OS options for these devices, from the default (“stock”) operating system that ships with the device, to community-led “custom firmware” alternatives. Below you will find a breakdown of each option, plus their advantages and disadvantages. When it comes down to it, I wouldn’t consider any OS option to be complete or perfect, but they each have their own excellent qualities.

The best aspect of these firmware options is that they all completely reside on microSD card, so you can swap between them without making any permanent change to the device itself. So really, your only cost when trying out each of these options is that you’ll likely want to have multiple microSD cards so you can swap between them.

If you don’t want to read through and determine the best firmware for you, here is my generic recommendation:

• BEGINNER: The stock operating system is just fine for most users. It has decent performance out of the box, and you can either enjoy the games that came with the default card, or easily add your own by dragging/dropping onto the card. All major features: WiFi, Bluetooth, HDMI, etc all work with the stock OS.
• NOVICE: If you like the stock OS but want to improve some of its functions, or if you want to make a backup card, I would recommend checking out the “modified” stock OS, which can be upgraded by a simple drag-and-drop, or you could flash it to a new card as a second copy.
• MINIMALIST: If you want an OS that “gets out of the way” so can just fire up your games with minimal distraction, check out MinUI.
• INTERMEDIATE: Once you’re ready to jump into the custom OS world, I would recommend KNULLI, which has a beautiful EmulationStation-based interface and a wide variety of features like a screensaver, theme downloader, onboard media scraping, and more.
• TINKERER: If you are a veteran of the handheld emulator scene, and like having the most advanced emulation performance (and don’t mind tinkering with configurations or re-flashing your card with each new update), then muOS is a really fun option. With some work, this can be tweaked exactly to your preferences.

For the starter guide video posted above, I show how to configure both stock (and modded stock), and KNULLI. For all the others, written instructions are also provided below.

Stock OS and microstutters: some users have noted that certain versions of Anbernic’s stock operating system have microstutters, particularly when playing within RetroArch. This is likely a screen configuration issue within their kernel or RetroArch video settings. There is no definitive “this version has it, this version doesn’t” solution at this point, but one solution is that custom firmwares like KNULLI and muOS (detailed below) don’t seem to have this issue. MinUI has also recently implemented measures to smooth out performance as well. So if you experience this on your device, the simplest solution may be to try those alternatives.

Stock (Anbernic) OS

Recommended microSD card setup: SINGLE CARD (64GB+)

The RG35XX devices will come with a 64GB card that features their latest stock operating system. This OS is surprisingly decent, albeit a little rough around the edges. At the very least, it will give brand new users a “plug and play” experience that allows them some pretty great gameplay out of the box, and options to upgrade later.

ROMs and BIOS: The main microSD card partition you will need to access on Stock OS will be called either “NO NAME” or “ROMS” depending on your device and firmware version. ROM files are found in the “Roms” folder of your stock OS card, and BIOS files are in the “bios” folder. They should already be pre-populated with the requisite files.

Using this OS is pretty intuitive. For the most part, you want to navigate to your games via the second menu “RA Games”, choose your system, then choose your game. It also have a Favorites function (press START while hovering over a game to add it as a Favorite), and you can also search for games or browse your play history. The stock OS also features a music player, video player, and eBook reader. You can add your files to the SD card via the corresponding folder (video, music, etc).

Your stock OS will also come with an “APPS” section. Its location depends on your device and OS version, but it will either be found within the “RA Games” section, or a dedicated App Center in the main menu. One of the most important apps is called Quick Shutdown, make sure you turn this option ON. Now, when in a game you can tap the POWER button and it will automatically save your progress and shut the device off. When you power the device back on, it will go back to where you were in the game — super handy. With the RG35XXSP, the Quick Shutdown app will also ask if you’d like to shutdown or sleep the device when closing the lid; I recommend shutting the device down, since the sleep power drain on Stock OS is pretty bad (about 4% battery per hour).

While in a game, you can press the MENU button to bring up the RetroArch quick menu, for more fine-tuned settings configurations. If you want to learn more about how RetroArch works, check out my guide, and I also explain some recommended adjustments in this section below.

Toggle analog/digital controls: One neat trick for devices that lack an analog stick (RG35XX Plus, RG28XX, and RG35XXSP), on more recent firmware releases, you can tap the POWER button while in a game and it will swap between a d-pad and left analog stick input. This is especially handy with N64, Dreamcast, and PSP titles that rely on analog stick controls. If your device is using an older firmware, you can update using the instructions below.

You can easily update the firmware to its latest release (with some added upgrades) by using “modded” stock OS, detailed in the next section. I highly recommend it, it will only take a few minutes to update.

If you lose the stock OS card, or if you want to upgrade to a newer SD card, you can download a new Stock OS image directly from Anbernic — but it’s not recommended that you go this route. That is because their SD card image is a full 64GB image, so you will need to make sure you have the internet connection and storage space for such a large file. If you want to download the official Anbernic firmware, head over to this page, and download the corresponding firmware file for your device. From there, you can flash this image to a 64GB (or larger microSD card) using tools like Balena Etcher or Rufus. This image will not come with games. For better results, I recommend downloading and installing the “modded” version of Stock OS maintained by developer cbepx-me (more information below).

Modded Stock OS

Recommended microSD card setup: SINGLE CARD (64GB+)

Developer cbepx-me has been meticulously merging Anbernic’s software revisions into a clean, improved software image. If you want to continue using the stock experience, I would recommend using this image. This solution can be used to flash a new card or to simply update your existing stock card.

Install on a new microSD card: It’s recommended that you install this image using a Windows PC for the best results. Head to this page, then navigate to the Google Drive link found on that page. Click on the folder that corresponds to your device, then Stock OS Mod > OS Image > “Base” image file. Once downloaded, use Rufus to flash this image file to your microSD card. After it’s been flashed, insert the card into your device, power it on, and allow it to go through the installation process.

When flashing a new card in Windows, it will create some additional partitions, which may create some additional windows pop-ups. You can ignore these, or if you’d like you can use Disk Management to unassign drive letter for those partitions to they don’t appear again.

Update your current stock microSD card: Head to this page, then navigate to the Google Drive link found on that page. Click on the folder that corresponds to your device, then Stock OS Mod > Update_Package > (name of 7zip upgrade file corresponding to your device). Once downloaded, use 7zip to extract the contents of the file, then find the “APPS” folder. Drag and drop its contents into the Roms > APPS folder of your microSD card, merging any files if prompted. Insert the card into your device then navigate to App Center > Apps (or RA Games > Apps if you are using an older version of Stock OS), then you should see a file that is named something like “RG35xxX_Upgrade_202xxxxx”. Run this app and it will upgrade your system.

Important note: If you are running an (older) 32-bit version of the Anbernic stock OS (dated prior to 25 June 2024), then you cannot update that stock OS to the more recent (64-bit) versions of modded stock. Instead, you will need to install modded stock to a new microSD card as detailed above, and then transfer any game files or saves from your old card to your new one.

Recommended Stock OS tweaks

These tweaks are written with the assumption that you’ve already updated the stock OS to the “modded” version in the section above, with the default settings elsewhere.

Change the boot logo: Insert your SD card into a computer, and then open the “Volumn” partition. Inside you’ll find a file named “bootlogo.bmp”; replace this file with another 640 x 480 (bmp) image with the same name to change the boot logo! Within the “ROMS” partition if you navigate to the anbernic > bootlogo folder you will find a bunch of sample bmp files you could use if you don’t want to make your own. There are also a collection of boot logos available here.

Enable RetroAchievements: For the devices with WiFi, you can set up RetroAchievements for most games. First, connect to your WiFi by going to Settings > Network Settings and adding your credentials. Once connected, go to Settings > Retroarch Settings > Start RetroArch. Once inside, go to Settings > Achievements and add your RetroArch credentials. You’ll need to make a free account on their website if you haven’t already. Once you have added your credentials, go to Main Menu > Configuration File > Save Current Configuration. Now you can exit RetroArch and you will connect to the RetroAchievements server every time you start a game.

Fixing the visual features of Stock OS: By default the stock overlays and shaders for GB, GBC, GBA, and other handheld systems are fantastic. But for home console systems, I found that the default scanline shader settings are a little too blurry and the stock overlays waste valuable screen real estate. So for systems like NES, SNES, and Genesis, I recommend the following adjustments:

• Go into Settings > RetroArch and start up RetroArch. Go into Settings > User Interface > Menu Item Visibility > Quick Menu and ensure that “Shaders” and “Save Core Overrides” is turned ON. Then back out to the main RetroArch menu and select Configuration File > Save Current Configuration, and then exit RetroArch.
• Start up a game from one of these systems, then press the M button to bring up the RetroArch quick menu
• Scroll down to Shaders > Load Preset > Interpolation and choose either the “Pixellate” or “Sharp Bilinear 2x Prescale” shaders, either will work great to balance pixels and are very similar.
• After choosing the shader, it will take you back to the main Shaders menu. Choose Save Preset > Save Core Preset
• Press the B button until you get to the Main Menu, then choose Settings > User Interface > On-Screen Overlay > Display Overlay > OFF
• Press the B button until you get to the Main Menu, then choose Settings > Video > Scaling > Aspect Ratio > Core Provided
• Press the B button until you get to the Main Menu, then choose Quick Menu > Overrides > Save Core Overrides

If you want to improve the visual experience even more on Stock OS, here are a couple other recommended adjustments:

• PS1 enhanced resolution: Open a PS1 game, then press the M button to bring up the RetroArch quick menu. Navigate to Core Options > GPU Plugin and turn ON the “Enhanced Resolution” and “Enhanced Resolution Speed Hack” options. This will output a full 480p resolution for games, when applicable. It will automatically save this setting for all PS1 games, so no need to do anything else.
• Game Boy LCD ghosting: Open a GB or GBC game, then press the M button to bring up the RetroArch quick menu. Navigate to Core Options > Interframe Blending and set it to “LCD Ghosting (Accurate)”. While in there, you can also adjust the GB colorization options but I think the default one is great. It will automatically save this setting for all GB/GBC games, so no need to do anything else.
• NES overscan: Open an NES game, then press the M button to bring up the RetroArch quick menu. Navigate to Core Options > Video and set both of the “Crop Horizontal Overscan” options to 8. This will reduce flickering on the sides of scrolling NES games like Super Mario Bros 3. It will automatically save this setting for all NES games, so no need to do anything else.

Add boxart/media: I recommend using Skraper to scrape your boxart directly from your ROM library. If you haven’t used this tool before, here is a quick video guide I made a while back for older systems, but the process will work here as well. Additionally, you can download boxarts individually using Libretro’s thumbnail repository (this will be handy if you have a smaller library). For the best results, you will want to resize the box art to no more than 300px wide, to reduce file sizes. The OS is expecting a 4:3 aspect ratio image, so if you use standard box art it will likely look squished (for basically everything but SNES games). Using Skraper, you could scrape screenshots or “miximage” options instead, which will generally output to 4:3 or similar. The boxart needs to be added to the same folder as your ROMs, but in a subfolder named “Imgs”. If you have a stock microSD card, you should already see that folder and some images within. The image file name needs to match the name of the ROM.

Add YouTube app: Yep, you can add a YouTube app to Stock and modified Stock OS following this simple guide.

KNULLI

Recommended microSD card setup: DUAL CARD (16GB & 64GB+)

KNULLI is a fork of Batocera, a popular custom Linux firmware. This OS takes advantage of several years’ worth of development and refinement, to provide a user interface that is mature and highly customizable. It also had on-board media scraping for Wi-Fi capable devices, which allows you to create a nice, rich user environment.

ROMs and BIOS: The main microSD card partition you will need to access on KNULLI will be called SHARE; within it, you will find folders named roms and bios, where you can add your files. Accessing the SHARE partition will vary depending on your setup, which we will discuss in the little blue box below.

Batocera folder system: If you need help figuring out which folder corresponds to which system, or the necessary BIOS files for each system, check out the Batocera Systems page on their wiki, which will apply to KNULLI as well.

INSTALL KNULLI: the installation process is relatively simple, but requires you to flash a new microSD card. Let’s do it.

• Head over to the KNULLI GitHub releases page, and download the img.gz file that corresponds to your device.
• Using a tool like Rufus (Windows) or Balena Etcher (Windows and Mac), flash the img file to a microSD card. You can flash it to 16GB or larger cards; if you are going with a two-card setup, I recommend 16GB. If you are going with a single-card setup, you can use any size you’d like (128GB is a pretty standard size).
  • If you run into any issues flashing the card, you can extract the img.gz file to its uncompressed img file format using a tool like 7zip; this should give a more stable flashing experience.
• Once the flash is complete, eject the SD card and put it into your device. If using a two-card setup, you can add the second card to the device now too. The OS card will initialize and you will be ready to start messing around with the KNULLI.

TWO-CARD SETUP: You can use a second SD card to store your game files separately from the operating system. The card can be in exFAT or EXT4 file format, although the team recommends using EXT4 (more information here) for improved PortMaster compatibility. To get started, boot up KNULLI with the second card inserted, then go into the Main Menu > System Settings > Storage > Storage Device and switch from Internal to the second card. Restart the device, during the reboot process it will populate your second card with the required folders. Once it has rebooted, shut down the device and add your games.

CREATE AN exFAT FILE PARTITION: by default, the storage partition for the main KNULLI microSD card is in EXT4 file format, which is only readable by Linux machines. This is done to enhance compatibility with certain PortMaster games. Having an EXT4 file format means that you won’t be able to drag and drop your games onto the card from Windows or Mac without using special third-party software. It is possible to use a second SD card (as detailed above), or reformat the SD1 card partition to exFAT, which will give you the ability to drag and drop games/BIOS files directly on Windows and Mac — but it will lose some PortMaster functionality (more info here).

To format your games partition to exFAT, open the main KNULLI menu by pressing START, then navigate to System Settings > Frontend Developer Options > Format a Disk and follow the prompts to format the partition to exFAT. It is recommended you do this BEFORE adding any game files.

If you want to keep the EXT4 file format (and widest PortMaster support), you can transfer your game files via network transfer. This is relatively simple once you get the hang of it, and full instructions are provided here (and below).

ADD GAMES VIA NETWORK: if you are using the standard EXT4 partition on a single card, you will need a Linux machine to read the SD card, or you will need to add games via network connection. The simplest method to do this is via Samba (SMB). First on your device go to Network Settings and enable WiFi, and connect to your local network. Now let’s begin:

• PC connection: open a Windows Explorer window, and in the navigation bar type in “\\KNULLI” or “\\192.168.86.XXX”, with XXX being the IP address specific to your device (which you can find in your device’s Network Settings once connected to WiFi). When trying to open one of the folders that appear, you may be prompted for a username and password, you can type “guest” as the username and leave the password blank. If you’d like to have more security, you can set up a proper username and password in System Settings > Security on your device.
• Mac connection: open Finder and in the top Menu Bar select Go > Connect to Server… and in the address bar that appears, type “smb://KNULLI” or “smb://192.168.86.XXX” with XXX being your device’s IP address. You may be prompted for a username and password, you can type “guest” as the username and leave the password blank. If you’d like to have more security, you can set up a proper username and password in System Settings > Security on your device.
• Now, on your computer you can wirelessly transfer your game and BIOS files.

You may encounter some issues with the controller mapping after you first install KNULLI. If this happens, go to Main Menu > Controller & BT Settings > Controller Mapping and remap your controls

Missing BIOS: if your BIOS files don’t match what KNULLI is looking for, you will get a pop-up warning about missing BIOS. You can go into the Game Settings > Missing BIOS Check to see what the discrepancy is, and you can fix it from there. Additionally, you can turn off the BIOS check before games start in case the mismatch doesn’t actually affect your gameplay.

UPDATE KNULLI: the team is working on OTA (wireless) updates, but for now, manual is the way to go. Thankfully it’s pretty easy.

• Go to the latest KNULLI release, and at the bottom of the post you will find the Assets section. Download the file labeled as “boot.tar.xz” that corresponds to your device, it should be about 2GB.
• Using a tool like 7zip, extract the file, you should see a file named batocera.update within the “boot” folder.
• Insert your SD1 card, and you will find a partition named BATOCERA, then navigate to the “boot” folder. Inside this folder, you’ll find a file named batocera. Delete this file and then drag/drop the batocera.update file we downloaded earlier into this boot folder.
• Eject the SD card insert it into your device, and upon boot your KNULLI installation will update to the latest release.

SCRAPE BOXART: one of the best features of KNULLI is the ability to scrape boxart directly on the device.

• To start, head over to ScreenScraper and create a free account if you haven’t already. Make note of your login credentials.
• On your device, press START to bring up the Main Menu. Navigate to the Scraper section, then in Scraper Settings > Account, add your USERNAME and PASSWORD credentials.
• From there, choose which types of media you wish to download. I like to use “Box 2D” as my image source, and I also turn on the “Scrape Videos” option. Everything else I leave unchecked.
• Once you are ready to scrape, select the “Scrape Now” button at the bottom of the main Scraper menu. Depending on the size of your library, it may take some time. Once done, go to the Main Menu > Game Settings > Update Gamelists to see the new media.

Screensaver: After scraping boxart/media, you can use the screensaver function. Press START to bring up the KNULLI menu, then navigate to UI Settings > Screensaver Settings. Here you can set Screensaver Behavior > Random Video. Now if you leave the device idle for 5 minutes while in the main menu, videos will start appearing. You can also initiate the screensaver by pressing SELECT while in the main menu. While a video is playing you can press SELECT to go to the next video, or START to being playing that game.

PortMaster: this wonderful app is already installed on KNULLI, you can find it in the Ports section of your menu. It requires WiFi connection to work. Not every PortMaster game works on KNULLI, but many do. To read more about PortMaster, check out their website. In KNULLI, you’ll find PortMaster within the Ports section; initially you will have to install the app, and then after that you can launch it.

Adding native Pico-8: It is possible to play Pico-8 games through the native app, but it is more of an advanced process compared to other OS options like muOS. Here is more information about the setup process.

KNULLI hotkeys: see the table above for important hotkeys (here is a full chart if you need it). There is more information on the KNULLI website as well. Note that while KNULLI has a quick shutdown option (Menu + POWER), this will not create an automatic save state nor will it boot back into your game when you power down. This is simply a fast way to turn off your device instead of going back to the main menu. So if you are going to use this function and want to save your progress beforehand, press Menu + Y to create a quick save, then power down the device. When you turn the device back on, start up your game, and press Menu + X to quick load your save. Adjusting hotkeys in KNULLI is possible, but a more advanced topic. Here is more information on the Batocera wiki page, as the process is the same.

Additional tips and tricks:

• When first starting KNULLI, you will hear background music. To turn this off, navigate to Sound Settings > Frontend Music > OFF, then back out of the menu for the change to take effect.
• There are a number of freeware games loaded onto the device when you first install it. To delete them, go to the ALL GAMES section of the frontend menu, and then press and hold the A button to bring up a sub-menu, then choose to delete each game.
• HDMI works, but for the best results, plug in the cable AFTER the device is already booted.
• KNULLI can also use the “Perfect Overlays” pack designed for muOS, if you’d like to add special overlays to GB/GBC/GBA games. Check out the “Configure Overlays” portion of the muOS section below for more information. The overlay pack should be placed in share > system > configs > retroarch > overlays (use SSH or SFTP to access this location, or move it over using KNULLI’s built-in file manager tool).
• Note that if you run into any problems saving the shader presets under the RetroArch Quick Menu, try going into the KNULLI Main Menu > Games Settings > Game Rendering & Shaders > Shader Set > NONE. This should remove any global presets so that your own per-core shader preset will work properly.

muOS

Recommended microSD card setup: DUAL CARD (16GB & 64GB+)

muOS (originally known as MustardOS) is a simple yet surprisingly robust custom OS solution for the RG35XX family of devices (and the original RG35XX handheld, too). Among all the community-developed software options, this one is best suited for the tech-savvy and tinkerers, and once you get the hang of it, you can really unlock the potential of these handheld devices.

For the best results, I recommend using a two-card setup with muOS, because updating this OS requires you to reflash the SD1 card.

INSTALL MUOS: download the latest software image from the muOS website. The team recommends flashing that downloaded image file using Raspberry Pi Imager, which is available on Windows, Mac, and Linux. Once you have flashed your card, insert it into your device and turn it on. This first installation can take quite some time. Once it’s done, shut down the device via the menu, and now we can add game files.

ROMs and BIOS: BIOS files go in the first microSD card (or the second card if you use the “Migrate to SD2” option described in the video above), in the MUOS > bios folder. Note that in the video above, I mentioned putting the dc_boot.bin BIOS file directly into the BIOS folder, but it needs to be placed into a subfolder named “dc” within the BIOS folder first.

When it comes to ROM files, muOS is unique because it doesn’t really care where you put them. You can throw them on the first card, or the second card. The only requirement is that you make a folder named “ROMS” in the root directory of whatever card you are using. From there, make subfolders however you’d like and put your games inside. Here is the structure that I used:

Arcade – MAME 2003 Plus
Arcade – Neo Geo
Nintendo – Game Boy
Nintendo – Super Nintendo
Sega – Dreamcast
Sega – Genesis…and so on.

Now, when you start up muOS again, you can browse your folders, pick your game, and start it up. Provided that you named the folders somewhat conventionally (like my example above), the system will guess which console you are launching and start it up. If it doesn’t know which system you are launching, it will prompt you to choose the system and your desired emulator core (after that first time, it’ll remember your preferences). If you ever want to re-assign the system or emulator core after the face, press SELECT when hovering over a game and make new choices.

Add artwork: You can add your artwork to your device, and they go in a specific location. On your SD1 card (or SD2 if you migrated to it as shown in the video above), navigate to MUOS > info > catalogue and within that folder you will see a list of game system folders. In each folder you will find three subfolders: box, preview, and text. “Box” refers to your boxart, “Preview” is for screenshots, and “Text” is for descriptive metadata. The images should be in .png file format, and the “Text” file should be txt. Each media file name will need to match its corresponding ROM name. As a general rule I use boxart images that are 300px in width, to reduce their file size. For more advanced users, you can try out Artie Scraper, which will scrape the boxart for you, but requires inputting Terminal commands.

UPDATE MUOS: unfortunately, as far as I can tell the only way to update to a new version of muOS is to flash a new SD1 card with the new software release, similar to installing the OS in the first place. This is why I recommend using a two-card setup, so that you don’t have to re-transfer your game files. Thankfully, muOS has handy backup and archive apps built-in, to ease the process of preserving your SD1 card contents (see the next section for more information). This is currently being worked on, and if you use the latest (“BANANAS”) version of the OS, chances are the next update won’t require re-flashing.

Archive / Backup Manager: muOS has the ability to create backups of important files, like your artwork, BIOS, configs, and RetroArch saves. You can create these backups using the Backup Manager, found in the Applications section. These will be created in a folder named “ARCHIVE” on your SD card. You can then pull these files from the SD card for safekeeping. Then if you need to reflash muOS, you can re-import these files using the Archive Manager.

General settings: In the Configuration > General Settings section there are some interesting options. Here you can enable/disable background music, choose which folder to start into when booting the device, turn on/off HDMI, and even adjust the color temperature of your screen. Additionally, within the configuration menu, you can also assign the correct device so that the controls will work as intended, in the “Device Type” section.

Themes: There are some themes already available in your muOS installation, you can swap them by going to Configuration > Theme Picker. You can also download community themes via their website.

WiFi Network and Web Services: these options can be found within the Configuration menu, and allow you to connect to your local network, enable Syncthing (to sync save files), navigate your device’s file system over a web browser, and sync the device clock to your network time. To use the File Browser, turn it on under Web Services, and then on your computer’s browser (connected to the same network as your device, type the devices IP address (found in the WiFi Network Configuration section) and add :9090 at the end. The address should look like 192.168.86.XX:9090. When prompted for a username and password, use “muos” for both fields.

PortMaster: this wonderful app is already installed on muOS, you can find it in the Applications > PortMaster section. It requires WiFi connection to work, and more games found in PortMaster are fully supported. Once you install a port, it will appear in the Ports section of your file browser. To read more about PortMaster, check out their website or my PortMaster guide.

Adding native Pico-8: It is possible to play Pico-8 games through the native app, and it is pleasantly easy to set up. Here are the instructions.

Additional tips and tricks:

• You can set favorites by pressing Y when hovering over a game. It will then be added to your Favourites section within the main menu. They will be sorted alphabetically.
• The muOS team recommends NOT using the stock SD card to flash their OS.

MinUI

Recommended microSD card setup: DUAL CARD (16GB & 64GB+)

MinUI is a custom launcher for a variety of devices, and it supports the entire RG35XX family.

ROMs and BIOS: It’s recommended that you use a two-card setup with MinUI. When you install the OS and launch it the first time, it will populate your ROM and BIOS folders on the second card, and afterwards you can add your files. For more information about specific BIOS files, you can find guidance in the readme file contained in your MinUI installation zip file.

Some major advantages of MinUI is that it is super simple — once you’ve added your games, the entire experience is very intuitive. This is the OS that I add to devices that I am going to gift to people who aren’t very familiar with electronics or technology. Additionally, most of the settings have been optimized for the device already, so there is no need to jump into the settings unless you want to. And finally, its unified settings menu means that you won’t have to bother learning how to navigate RetroArch’s clumsy menu system.

MinUI also features a simple interaction experience. For example, to power off your device, simply hold the power button. If you’re in a game when you power if off, it will create a quicksave file, and the next time you boot the device up, it’ll take you back to that same spot in your game.

The main disadvantage of MinUI is that it only supports up to PS1, and has no WiFi or Bluetooth support.

INSTALL MINUI:

• Download and unzip the latest release from their GitHub page. You will at least need the “base” zip file but you can also grab the “extras” one for additional emulators like Game Gear, Pico-8, PC Engine (TurboGrafx), Super Game Boy, Virtual Boy, and Master System.
• If your second microSD (SD2) card is larger than 32GB, it is recommended that you format it to the FAT32 file system. This will make the card cross-compatible with other devices like the Miyoo Mini, original RG35XX, and TrimUI Smart.
  • If using Windows, use the guiformat tool to format the card to FAT32.
  • If you have a Mac, “Erase” the disk using the Mac’s built-in Disk Utility app, and select MS-DOS (FAT) file format.
• In the unzipped MinUI base folder, navigate to “rg35xxplus” > dmenu.bin, and place that file to the root of the “NO NAME” or “ROMS” partition of your stock SD card (it’s the partition that contains the “anbernic” folder, it has various names depending on the device and stock OS version).
• Take the MinUI.zip file from the unzipped MinUI base folder and put that in the root directory of your second microSD (SD2) card.
• Put your microSD cards into the device, and let it run through the installation process. Once complete, you will be greeted with a blank menu. Power off the device by pressing and holding the POWER button for a couple seconds, then put the SD2 card back into your computer.
• On the card, you should now see ROMs and BIOS folders, among others. Add your game and BIOS files according to the MinUI readme file.
• If you’d like, you can drag and drop the contents of the “Extras” zip file into the SD2 card (choose to “merge” the files when prompted) for additional systems like Game Gear and Virtual Boy, and then add those ROMs/BIOS files as well. Instructions are also provided in the “extras” readme file.

To update MinUI, download the latest release (the “base” zip file), unzip it, and move the MinUI.zip file onto your SD2 card. The next time you boot your device, it will update.

If you want to revert back to Stock OS, insert your SD1 card into a computer, and rename the dmenu.bin file to something else, like dmenu_disabled.bin. If you’d like, you can change it back to dmenu.bin to get back into MinUI.

ADDITIONAL MINUI TIPS:

• While in a game, press the MENU button to bring up an options screen. Here you can quit your game, load/save your state, and browse more options. Note that by default, games will not auto-save or auto-load, so be sure to save your progress using in-game saves or save states.
• When navigating the games lists, if your game has a save state already saved to it, you can press the X button instead of the A button to launch the game directly into your save state — it’s super fast and handy.
• The options menu has a variety of powerful options, and handy subtitles to explain each option. You can set aspect ratio, scanlines, button mapping, hotkey mapping, and more on a system-level or on a per-game basis.
• MinUI has a quicksave function, simply power down the device while in a game and it will save your spot, and resume it when you power the device back on.
• MinUI has a sleep function, simply tap on the power button while in game and tap it again to resume. When in the main menu, the screen will automatically go to sleep if you don’t press anything for a minute. Tap the power button to bring it back up — but if you leave it in sleep for over two minutes, the device will just power down to save on battery life.
• MinUI has support for multi-disc games, check out the readme.txt file for more details.
• MinUI has HDMI support, and scales games properly.

RY’S MINUI ADD-ON PAKS: there is a community package that will expand your gaming options with MinUI on RG35XX devices. This will add stock emulators into the MinUI interface so that you can play Dreamcast, Nintendo DS, Nintendo 64, PSP, and arcade games within the MinUI interface. It also contains a number of tools that includes an eBook reader, music player, and more. To install this package, head over to their GitHub page and follow the instructions in their readme file.

GarlicOS 2.0

GarlicOS 2.0 is an updated version of the original GarlicOS (made for the original RG35XX handheld in 2022). This OS is meant to be used across multiple devices, including those on other chipsets (even Android-based devices).

This OS is still in an early alpha state, and while it’s available for the public, I would recommend waiting until it is in a beta release state unless you want to be at the forefront of Garlic testing. If you would like to test it out and provide feedback to the developer, here is a link to the installation package.

ROCKNIX

Members of the ROCKNIX (formerly JELOS) team are working to potentially port their OS to the RG35XX family of devices. This is still very much a work in progress, and may not come to pass, but I will update this guide as we hear more about it.

Getting ROCKNIX ported to these devices would be a big win, since it has stable and widespread support across a variety of handhelds. This will allow users to take their SD2 (games) card and swap them between devices for easy ROM/saves compatibility. ROCKNIX also features extensive documentation, preconfigured optimizations, EmulationStation-backed configuration options, Portmaster support, easy multiplayer, robust networking features (including OTA updates), and much more.

Shaders, overlays, and more

I recently created a shaders and overlays guide for 4:3 480p screens, which includes all of the RG*XX devices. This is a great option is you want to really max out the screen effects on your device — you can balance pixels, fill out any black borders, and even create a CRT television effect like you can see in the thumbnail above. In addition to the video guide, I’ve also made a comprehensive written guide. You can apply shaders and overlays to all of the OS options available for this device, for the most part (MinUI is somewhat limited but still has scanline/grid overlay options).

Be sure to note the “Other OS Considerations” section of the written guide (and video) for some tips and tricks related to some of the OS options for these devices. There is also a section at the end of the written guide with recommended shaders and links to overlays for the RG Cube XX.

Hardware mods

One of the best things about these devices is that they are fun to mess around with. You can customize the look and feel of each handheld to personalize your overall experience. For example, in the video above I apply a quick “tape mod” to the RG35XXSP to soften the buttons and dampen their clickiness. This is all personal preference, but it has definitely enhanced my experience with the handheld. Note that recent updates to this device have generally solved the clickiness issue with the RG35XXSP.

Here are my tape layer recommendations:
D-Pad, SELECT/START/Menu buttons: 2 layers each
Face buttons: 3 layers each
Shoulders/triggers: 2 or 3 layers each

In addition, you can find stickers and replacement buttons for each handheld on Etsy, created by community members. One of my favorite shops is Sakura Retro Modding — they feature a number of difference options for each device and have been making similar mods for years.

Another great example is EpicPrintingShop, who makes reversible grips/cases for most Anbernic devices, to both protect your device and improve its ergonomics.

Changelog

26OCT2024
– fixed broken muOS link
– added Artier Scraper muOS link

24OCT2024
– added RG*XX comparison video
– added links to RG Cube XX

16OCT2024
– added muOS video guide
– updated muOS section

02SEP2024
– added section related to shaders and overlays guide
– removed muOS shader/overlays section to reduce conflicts with shader guide

27AUG2024
– updated Syncthing link in muOS section
– updated link to muOS theme repository

24AUG2024
– added Charging and safety section
– added Hardware mods section
– updated links to new devices (RG40XX)
– updated pros/cons based on recent updates

04AUG2024
– added new overlay section in the muOS part of the guide

02AUG2024
– added notes about lid support in KNULLI and muOS
– adjusted pros/cons in muOS to reflect new updates
– added note about new muOS update method
– added link to muOS “perfect” overlays set

10JUL2024
– added more context re: exFAT and EXT4 file systems when using KNULLI
– added note about updating 32-bit stock OS to 64-bit modded stock OS

05JUL2024
– added instructions to format SD2 to FAT32 when using MinUI
– updated advantages/disadvantages to muOS thanks to new features added to Refried Beans

14JUN2024
– added YouTube app for Stock OS
– added wording re: copy/pasting files to new microSD card
– various tweaks and clarifications

07JUN2024
– published guide