Retrode 2026: Dump SNES + Genesis in 14 Steps, 30 Min

There is a specific kind of person who owns an original Super Nintendo cartridge, a perfectly good emulator, and a low-grade guilt that the two have never been introduced. The Retrode is the appliance that performs the introduction. Per its own Wikipedia entry, it is "a USB adapter for legacy video games": you seat a real cartridge in one end, run USB out the other, and the device appears on your computer as an ordinary removable drive with a ROM file already sitting on it. No capture card. No de-soldering. No photographing a CRT and calling it archival. You copy the file off, and that file is a bit-for-bit dump of silicon you physically own.

This guide is the long version: fourteen numbered steps to pull a clean SNES or Sega Genesis dump, the RETRODE.CFG edits that let you back up (and restore) battery saves, the co-processor cartridges that will quietly defeat you, how to flash the frozen 2016 firmware without bricking the thing, and an honest read on the Retrode 3 — the successor whose hardware is finished and whose software is not. Budget about thirty minutes for your first cartridge and five for every one after.

What a Retrode Actually Does

The one-sentence definition, then the nuance

The Retrode is a cartridge reader that masquerades as a USB flash drive. Slot in Super Mario World, plug in USB, and the operating system mounts a small removable volume containing SUPER MARIOWORLD.SFC — the game ROM — and, on cartridges with a battery, a .SRM file holding your saved game. It is driverless on Windows, macOS, and Linux because it speaks two standard USB languages at once: mass storage for the files, and USB HID for the controller ports on its top edge, which turn a real SNES or Sega pad into a plug-and-play gamepad. That dual identity — a drive and a joystick, at the same time — is the entire trick.

The nuance is that "dump" means read, not copy freely. ROM is Read-Only Memory; the Retrode presents those files write-protected, because there is nothing to write back to a mask ROM. Your battery-backed save RAM is a different animal, and it is where most of the interesting configuration lives — that is the SRAM section, and it is the only place the word "write" legitimately appears in this workflow.

Why anyone still rips silicon in 2026

Because the alternative is trusting someone else's dump, and 2026 is the year that stopped being a casual decision. The preservation scene has, as the Retrolize 2026 retrospective argues, shifted from simple nostalgia into a professionalized, contested ecosystem. First parties are now in the room: Nintendo Switch Online's Expansion Pack folded in GameCube titles this year, and — as the June 2026 Nintendo Direct underlined — the company even resurrected the Virtual Boy through a dedicated accessory for the Switch and Switch 2. On the software side, the Dolphin team shipped 2026 support for Sega/Namco/Nintendo Triforce arcade code and untangled some genuinely nasty GameCube memory behavior. All of that is playback. None of it hands you the bits off your cartridge, with your save, verified by your checksum.

That is the preservation argument, and it is the one the University of Maryland's MITH lab made when it used a Retrode to archive SNES games. If you want the same authority over your own shelf — and if you plan to play those dumps on a handheld or a cabinet later, whether that is a Miyoo Mini Plus in your pocket or a full living-room build — you dump it yourself. Nobody has ever regretted owning the verified copy.

What the Retrode is not

It is not an EverDrive or a flash cart: on its own it will not let you load a folder of ROMs onto an SD card and play them on original hardware. It is not an emulator; it produces files and stops. And it is not a curated-library handheld like the Evercade Nexus, the cartridge-based unit arriving in October 2026 — that device plays licensed collections off proprietary carts and dumps nothing off yours. The Retrode occupies the opposite corner: it reads your legacy carts and leaves playback to whatever you point the files at, from a Batocera install to a RetroPie box. It is a scanner, not a jukebox, and understanding that distinction saves you from buying the wrong device twice.

Retrode 2 vs Retrode 3 in 2026

The Retrode 2 — the one that ships

Everything in this tutorial targets the Retrode 2, because it is the only Retrode you can put a cart into today. It sells through DragonBox in Europe and Stone Age Gamer in the States. Pricing in mid-2026: DragonBox lists the base unit around €64.90 (the official site quotes an SRP of "EUR 65 / USD 85") with plug-in adapters at €25 each or €65 for all three; Stone Age Gamer lists it at $99.99 with adapters at $39.99 apiece. The box is spartan — the unit, a USB cable, an instruction sheet — which is honest, because the unit does not need more.

The hardware lineage explains the frozen firmware, so it is worth thirty seconds. Matthias Hullin conceived the original Retrode on the OpenPandora forums in 2009; Retrode UG ran it out of Germany until it wound down in the summer of 2013; the second revision — the Retrode 2 you buy now — came back through OpenPandora GmbH in March 2015 and lives at DragonBox today. Physically it is a slab with two cartridge slots: the short lower slot takes Sega Mega Drive / Genesis carts, the wide upper slot takes SNES / Super Famicom, and four controller ports (two SNES, two Sega) line the top edge alongside the two function buttons.

The Retrode 3 — finished hardware, unfinished software

The news peg for 2026 is the Retrode 3, and the honest framing is: the hardware is done, the software is not, and you cannot order one. The official site calls it the successor to the Retrode 2 and says outright that the team is still working on the software; the target is availability by the end of 2026 at a price under €100, with no exact date and no final price committed. There is no cart button and no checkout button — only a "notify me" pre-registration on the DragonBox page. DragonBox's own social posts describe "10 fully working prototypes" and an open call for developers, which is precisely what "hardware finished, software pending" looks like from the outside.

What changes in the 3 is the entire interface model. Where the Retrode 2 is a USB mass-storage drive, the Retrode 3 registers as a USB-Ethernet device and serves its whole UI from a web browser — no drivers, no mounted volume, just a local page that dumps carts, backs up SRAM, and (the new trick) writes flash carts. Mega Drive flashing via a DragonDrive cart reportedly works today; SNES and Atari Lynx flashing are slated for launch. It runs Debian on a Linux SoC, adds built-in Wi-Fi, and finally introduces an NES slot alongside SNES and Genesis. It is fully open — four public repositories cover the OS, kernel, userspace, and hardware — and DragonBox calls the SD-card OS "practically unbrickable" because a bad state is a reflash, not a paperweight. It is built on Sanni's Cart Reader, and the plugins are cross-compatible in both directions.

The MIPS-or-ARM question nobody has settled

One deadpan caveat, because The Machine reads the whole page and not just the headline: DragonBox cannot decide what chip is inside its own product. The top of the description says "MIPS processor." Further down the same page it says the device has "its own ARM processor and a Linux operating system (Debian)." Both cannot be true. Until the software ships and someone runs uname -m on real hardware, treat the CPU as "a Linux SoC, architecture to be confirmed" and do not quote either figure as settled. It is a small thing, but a product page that contradicts itself on the processor is a fair signal that the software really is mid-flight — which is exactly why you buy the 2 in 2026 and bookmark the 3.

Prerequisites and Versions

Hardware you need on the desk

You need the Retrode 2 unit and its bundled USB cable, and a host machine with a free USB-A port. Plug directly into the machine — a rear port on a desktop, a native port on a laptop — and not into a bus-powered hub, because the Retrode draws its power over USB and a marginal hub is the single most common cause of a mount that never appears or a dump that drops out halfway. You need the cartridges, genuine and ideally clean. You need 99% isopropyl alcohol and a lint-free swab or soft brush for the edge contacts — not a cotton bud that sheds fibres, and emphatically not your breath. And if you are dumping N64, Game Boy, or Master System, you need the matching plug-in adapter.

Software — there is almost none

For the dump itself, nothing. Windows, macOS, and Linux all mount the Retrode with no drivers; the historical Pandora and Caanoo handhelds did too. You need a file manager to copy files, and a terminal if you want to verify (Linux and macOS ship md5sum/sha1sum; on Windows use CertUtil or a checksum GUI). Recommended but optional: a current No-Intro DAT to verify your dumps against, and an emulator or frontend to prove they run — RetroArch with the right core, or a full frontend OS like the two linked above. Everything that matters happens on a drive that behaves like any other USB stick.

Firmware you should be running

The Retrode 2 firmware line is frozen at 0.18 — 0.18c is the last stable build, dated April 2016, with 0.18d beta 3 as the last beta floating around. The configuration-file feature you will use for saves has existed since 0.17g, so anything from the 0.18 line has it. Ignore any search result claiming a "v0.22 with enhanced SNES chip support": there is no v0.22. It is a persistent forum myth, and chasing it is how people end up flashing a random hex file into a working device. The real 0.18 changelog is modest and honest — better N64/GBA size detection, a LUFA library refresh, a Master System plug-in bugfix, and, genuinely useful, Master System SRAM reading. The stack is Dean Camera's LUFA running on an Atmel AT90USB646 microcontroller. You do not need to know that to dump a cart; you need it to flash firmware, which is covered later.

The 14-Step Dump: SNES and Genesis to ROM

Read this before you plug anything in

Two rules prevent most of the grief. First: never yank a cartridge while the drive is mounted. Hot-swapping can corrupt an on-cartridge save, and the user guide says exactly that — treat every cart change as eject-first. Second: if you are using a plug-in adapter (N64, Game Boy, Master System), connect the adapter to the Retrode before you connect the Retrode to the computer, because the firmware detects the adapter at power-on and will not notice one plugged in late.

Steps 1 through 14

1. Inventory the box and inspect the cartridge. Confirm the shell is genuine and the label matches the game. A repro cart or a cracked shell wastes the next ten minutes, and you want to know that before you clean and seat it.
2. Clean the contacts. 99% isopropyl on a lint-free swab, wipe the edge connector, let it flash off. Oxidized contacts are the number-one cause of garbage dumps and half-detected carts. Do not blow into the slot — you are depositing moisture on the pins, which is the folk remedy that ate a generation of NES carts.
3. Connect any plug-in adapter first. If you are dumping N64, Game Boy, or SMS, seat the adapter on the Retrode now. The firmware reads the adapter at power-up; connect it after USB and it stays invisible.
4. Seat the cartridge in the correct slot. Upper wide slot = SNES/SFC; lower short slot = Genesis/Mega Drive. Push it firm, level, and fully home. A cart seated at an angle reads intermittently and produces a truncated or mis-sized file.
5. Connect USB directly to the host. A native port, not a hub. The Retrode is bus-powered, and a weak hub browns it out — this is the difference between a clean mount and a phantom failure you will chase for twenty minutes.
6. Wait for the mount and watch the LED. The removable volume appears; the activity LED lights on ROM/RAM access. If nothing mounts within a few seconds, stop and troubleshoot rather than re-seating the cart on a loop, which only wears the contacts.
7. Open the drive and read RETRODE.CFG. Its presence confirms the firmware mounted its config, and it is the file you will edit for saves. If the volume mounts but shows no CFG, the firmware did not initialize cleanly — re-seat and remount.
8. Confirm the ROM file and sanity-check its size. A 4 Mbit SNES game is 512 KB; a 32 Mbit game is 4 MB. A size that is suspiciously small, or a clean fraction of what you expect, means a bad read or a misdetected mapper. Fix it now, while the cart is still on the desk.
9. Copy the ROM off the drive. Drag it, or use cp/rsync to real storage. Never work off the mounted volume — copy first, then verify the copy, so a re-seat or an unplug never touches your working file.
10. Verify the checksum. Hash the file with md5sum or sha1sum and compare against the current No-Intro DAT. A matching hash is the entire difference between "a file" and "a preservation-grade dump."
11. Unlock SRAM writing only if you need it. To restore a save to a cart, edit RETRODE.CFG and set sramReadonly to 0. By default the Retrode write-protects the save so you cannot clobber a battery save by accident; you flip the switch deliberately.
12. Back up the save. Copy the .SRM off the drive. The battery in a thirty-year-old cart is a countdown, and this file is the only copy that outlives it. Do this even when you have no intention of restoring anything.
13. Eject safely, then swap. Unmount the volume, then unplug or eject the cart. The guide is explicit that hot-swapping can damage on-cartridge saves; the ten seconds you save by yanking it is not worth the save file you lose.
14. Load the dump in an emulator to confirm. Point RetroArch or your frontend at the file and boot it, then load the save. The only proof a dump is good is that it runs and the save comes back — a hash tells you the bytes are right, a boot tells you they are the right right.

What a clean dump looks like

After a good mount, the volume listing is short and legible — note that the ROM is read-only (r--) while the save is writable (rw-), which is the firmware's default protection doing its job:

$ ls -la /Volumes/RETRODE/
-r--r--r--  1 you  staff  524288  Jan  1  2016  SUPER MARIOWORLD.SFC
-rw-r--r--  1 you  staff    2048  Jan  1  2016  SUPER MARIOWORLD.SRM
-r--r--r--  1 you  staff     512  Jan  1  2016  RETRODE.CFG

On Linux, the kernel log confirms the device came up as ordinary USB mass storage — no vendor driver, no proprietary tool:

$ dmesg | tail -n 4
usb 1-1: new full-speed USB device number 14 using xhci_hcd
usb-storage 1-1:1.0: USB Mass Storage device detected
scsi host6: usb-storage 1-1:1.0
sd 6:0:0:0: [sdb] Attached SCSI removable disk

Backing Up SRAM Saves

Why your first save backup looks empty

The Retrode ships write-protecting the RAM file — the Retrode user guide notes the RAM files are "by default write-protected." That is a feature, not a fault: it stops you from accidentally overwriting a battery save with an empty buffer. But it confuses first-timers, who see a .SRM that refuses a write and conclude the cart is dead. It is not; the firmware is guarding the save. To write saves back to a cart, you tell it to stand down — deliberately, one line at a time.

Editing RETRODE.CFG on the drive itself

The config file lives on the mounted volume, so you edit it in place. Open RETRODE.CFG in a plain-text editor, change one line, save it back to the drive, and re-seat the cart (or unplug and replug) so the firmware re-reads it. The LED blinks when the firmware writes the config back. The only key that matters here is sramReadonly:

# RETRODE.CFG — enable writing saves back to the cartridge
# 1 = protect (default), 0 = allow writes
sramReadonly    0

With that at 0, copying a .SRM onto the volume writes it into the cart's battery RAM on supported cartridges. Set it back to 1 the moment you are done writing, because the default exists for a reason and a stray file copy with the guard down is how you overwrite a save you meant to keep.

The .SRM file and what emulators expect

The save file the Retrode exposes is raw SRAM — the same format most emulators consume as .srm. A SNES cart shows <game>.sfc paired with <game>.srm; a Sega cart shows <game>.bin paired with <game>.srm. Drop the ROM and the save side by side with matching base names in your emulator's folder and it will pick up the save automatically. Two caveats keep you honest: Sega SRAM support went through a long "under development / beta" phase, so verify Genesis saves by loading them rather than trusting them blind, and Game Boy Advance save types — both SRAM and flash — are still listed as pending, so do not rely on the Retrode for your GBA clock-battery saves.

The Co-Processor Trap

What dumps without complaint

Most SNES enhancement chips are transparent to the Retrode, because dumping the ROM and running the chip are separate problems — the Retrode reads the mask ROM, and your emulator supplies the chip behavior. The two people worry about and should not: the Super FX chip (Star Fox, Super Mario World 2: Yoshi's Island, Doom) and the DSP1 (Pilotwings, Super Mario Kart) both dump fine. The official FAQ confirms it: Super FX and DSP1 are supported, because a modern emulator handles the chip once you have the ROM in hand.

What quietly defeats it

Three families do not dump cleanly, and it is far better to know before you spend an afternoon: the SA-1 chip, the S-DD1, and Sega's Virtua Processor. SA-1 is the painful one because it sits under some beloved carts — Super Mario RPG, Kirby Super Star, and Kirby's Dream Land 3 all use it. S-DD1 covers Star Ocean and Street Fighter Alpha 2. Sega's SVP is essentially one cartridge, Virtua Racing. Point the Retrode at any of these and you will not get a usable dump; the FAQ lists SA-1, S-DD1, and the Sega Virtua Processor as explicitly unsupported. This is a hardware limit of an 8-bit reader, not a firmware bug you can flash away.

How to tell before you waste the afternoon

Two tells. First, know your library — the SA-1 and S-DD1 game lists are short and well documented, so a thirty-second lookup before you dump saves the frustration. Second, watch the file size and the header. An SA-1 cart often mis-sizes or produces a header the Retrode cannot title, so the drive shows a garbled or generic filename and a size that does not line up with the known ROM. If the size does not match a No-Intro entry and the game is on the SA-1 list, stop; no amount of re-seating fixes an unsupported mapper. For those titles, a Sanni Cart Reader build or a full desolder-and-read is the honest path — and it is exactly the gap the Retrode 3's Sanni lineage is meant to close.

Plug-In Adapters

The three that still ship

Beyond the two built-in slots, DragonBox still sells three plug-in adapters that share the top connector: N64, a Game Boy family adapter (original GB, Game Boy Color, Game Boy Advance), and Sega Master System. Each is €25 from DragonBox or $39.99 from Stone Age Gamer. They extend the same mass-storage-drive workflow to those cartridges — seat the adapter, seat the cart, and the ROM appears on the same volume you already know. There is no separate software and no separate mode; the adapter simply teaches the existing firmware a new pinout.

Voltage, order of operations, and the save caveats

Read the fine print, because it is per-adapter. The N64 adapter dumps ROMs fine, runs at 3.3V, supports up to two controllers, and must be connected before USB; N64 save support is listed as "firmware support pending," so treat cart saves as not-yet. The Game Boy adapter dumps GB, GBC, and GBA ROMs; GB and GBC SRAM reads work, but GBA SRAM and flash saves are still pending — and mind the voltage split, GB/GBC at 5V, GBA at 3.3V. The Master System adapter dumps ROMs and, since the 0.18 firmware, reads SMS SRAM; be aware that SMS carts carry no in-header title, so the filename comes out generic and you will rename by hand.

The exotic adapters that died with their connectors

There used to be more. Various one-off and third-party adapters existed over the Retrode's life and have since been discontinued, mostly because the physical connectors became unobtainable. A couple of durable community facts survive from that era and still matter at the desk: the SNES mouse only works in the left controller port, and a Sega 32X adapter works when connected without its power supply, while a Super Game Boy adapter does not work at all — it is effectively a whole console, and the Retrode will not drive it. If a listing promises a working adapter for some obscure format, assume it is historical unless DragonBox currently stocks it.

Firmware and DFU Flashing

Why the firmware stopped in 2016

The Retrode 2 firmware is frozen at the 0.18 line — 0.18c stable, dated April 2016, with 0.18d beta 3 as the last beta. That is not neglect so much as a product that reached its ceiling on an 8-bit AVR. The microcontroller is an Atmel AT90USB646 running Dean Camera's LUFA USB stack, and the config-file feature you used for saves has been present since 0.17g. If a search result promises a 0.22 with "enhanced chip cart support," close the tab — it does not exist, and chasing it is how people flash a random hex file into a working device and then wonder why it stopped mounting.

Entering DFU mode without bricking anything

You only reflash if you are genuinely on an older build or recovering a bad flash; a working Retrode on 0.18c needs nothing done to it. To flash, you put the AVR into its DFU bootloader: hold the HWB button (labeled 7 on the board — the same button firmware uses for custom functions), press and release RESET (button 8), then release HWB. The device re-enumerates as an Atmel DFU bootloader. On Linux you can confirm it:

$ lsusb | grep -i atmel
Bus 001 Device 020: ID 03eb:2ff9 Atmel Corp. atmega/at90usb DFU bootloader

That 03eb:2ff9 is the documented DFU ID for the AT90USB646. If you see it, you are in the bootloader and safe to flash. If you do not, you never entered DFU — repeat the HWB/RESET sequence rather than flashing blind into normal mode.

Flashing with FLIP or dfu-programmer

On Windows, Atmel's FLIP is the GUI path: select the AT90USB646, open the .hex, then erase, program, and verify. On Linux or macOS, dfu-programmer is the command-line equivalent:

# with the Retrode in DFU mode (03eb:2ff9):
dfu-programmer at90usb646 erase --force
dfu-programmer at90usb646 flash retrode_0.18c.hex
dfu-programmer at90usb646 reset

Erase, flash the official hex, reset. After the reset the device leaves the bootloader and returns as a normal Retrode drive. Do not interrupt the flash, and only ever flash the official firmware image — the AVR is forgiving, but it is not magic, and there is no reason to feed it anything but the vendor hex.

Common Pitfalls

The ones that cost you saves

Hot-swapping carts. The single most expensive mistake. The user guide is blunt: swapping a cartridge while the Retrode is live is "possible, but it can potentially damage on-cartridge savegames," and it advises you eject or unplug first. Treat every swap as an eject-first operation, full stop. Writing to a cart you did not mean to. If you left sramReadonly at 0 after a restore, a stray file copy can overwrite a battery save. Set it back to 1 the instant you finish writing, and make that a reflex rather than a resolution.

The ones that cost you time

Dirty or oxidized contacts. Garbage dumps, half-detection, and phantom size errors nearly always trace to the edge connector. Clean with 99% isopropyl; never blow into the slot. Bus-powered USB hubs. The Retrode browns out on marginal hubs — mount failures and mid-dump dropouts that look like a dead unit. Plug into a real port and the "dead" Retrode resurrects. Assuming SA-1 games will "just work." They will not; Super Mario RPG and the SA-1 Kirby titles are unsupported, and re-seating them forty times changes nothing but your patience.

The ones that cost you a good dump

Trusting size over checksum. A file of the right size can still be a bad read; only a No-Intro hash match certifies it. Skipping the header rename on Master System. SMS carts have no in-header title, so dumps come out generically named — rename them before they pile up unidentifiable. Believing a "v0.22" firmware exists. It does not; flashing something you found because you believed it does is how a working unit becomes a support ticket.

Troubleshooting Table

How to read this table

Left column is the symptom at the desk; right column is the fix in order of likelihood. Work top to bottom. Most "dead Retrode" reports are a hub, a contact, or a cart that is not fully seated — not a dead unit.

When it is actually the unit

If a known-good cart, on a direct USB port, with clean contacts and a confirmed 0.18c firmware, still will not produce a valid dump across two different computers, then you are in warranty territory — contact DragonBox or Stone Age Gamer. That is rare. The Retrode is a simple, robust device, and nearly every failure is environmental rather than a fault in the hardware.

Advanced Tips

Verifying against No-Intro like you mean it

A dump you have not verified is a rumor. Build the habit: hash every dump and compare against the current No-Intro DAT. On the command line it is one line per file, and you can batch a whole shelf at once:

$ md5sum *.sfc *.bin
c8f6...e11a  SUPER MARIOWORLD.SFC
9a3d...74bc  SONIC THE HEDGEHOG.BIN
# compare each hash against the matching entry in the current No-Intro DAT

(The hashes above are illustrative — the point is the workflow, and the match against No-Intro is the only thing that certifies a dump.) Keep the verified ROMs, the .srm saves, and a note of the DAT version together; that bundle is what "preservation-grade" actually means, and it is what makes your dumps portable to any frontend you build later.

A preview of the Retrode 3 browser workflow

When the Retrode 3 software ships, the flow changes shape. Instead of a mounted drive, you open a local web page the device serves over USB-Ethernet, and you dump, back up SRAM, and — new — write flash carts from the browser. Mega Drive flashing via DragonDrive is reported working; SNES and Lynx are slated for launch. Because the OS is Debian on an SD card and the whole stack is open across four repositories, a bad update is a reflash, not a brick. Until then, the 3 is a "notify me" button and ten prototypes, and the 2 is what dumps your carts today. That is the correct order of operations for a device whose own page cannot agree on its CPU.

Cross-pollination with Sanni's Cart Reader

The Retrode 3 is built on Sanni's open Cart Reader lineage, and DragonBox says the plugins are cross-compatible in both directions. Practically, that means the ecosystem that already dumps the hard cases the Retrode 2 cannot — the SA-1 and S-DD1 titles, the more exotic formats — is converging with the Retrode line rather than competing with it. If you hit the co-processor wall today, a Cart Reader build is the bridge, and it is the same lineage your next Retrode will run. For libretro-side playback and core choices once the files exist, the libretro documentation is the reference to keep open.

The Complete RETRODE.CFG

The confirmed key vocabulary

The canonical RETRODE.CFG lives on the Retrode's own volume, and the historical online documentation has gone dark — retrode.org now redirects to retrode.com, and the old CFG page 302s away. So treat the syntax below as illustrative of the format; the exact comment character and value units are the firmware's to define. But the key names are the confirmed vocabulary the firmware actually reads, and the config feature has existed since 0.17g. Use this as a map of what is tunable, and edit the live file on the drive.

A complete, commented reference file

# ============================================================
#  RETRODE.CFG  —  illustrative reference (Retrode 2, fw 0.18c)
#  Key names are confirmed; syntax shown is format-illustrative.
#  The live file lives on the mounted RETRODE volume.
# ============================================================

# --- Save (SRAM) behavior ---
sramReadonly     1        # 1 = protect saves (default), 0 = allow writes
segaSram16bit    0        # Sega 16-bit SRAM handling toggle
sramExt          srm      # extension used for the save file

# --- System / detection overrides ---
forceSystem      auto     # auto by default; e.g. GG to force Game Gear
forceSize        0        # 0 = auto-detect ROM size; override if misdetected
forceMapper      0        # 0 = auto; override a mis-read cartridge mapper
detectionDelay   0        # delay before the firmware reads the cart

# --- Filenames ---
filenameChksum   0        # append a checksum to the output filename
snesRomExt       sfc      # extension for SNES/SFC ROM dumps
segaRomExt       bin      # extension for Sega ROM dumps

The one edit most people actually make

Ninety percent of the time you touch exactly one line — sramReadonly — and only when you are restoring a save to a cart. Set it to 0, copy the .srm, set it back to 1, done. The forceSystem / forceSize / forceMapper trio is your escape hatch when a cart is misdetected; a Game Gear cart read as Master System is the classic case, and forceSystem GG fixes it. Everything else is fine at defaults. That is the whole appliance: a drive that reads your cartridges, a config file with one switch that matters, and thirty years of games that finally have somewhere to go — whether that is a Retroid Pocket in your hand or a shelf of verified dumps that outlive the batteries in the carts. Do it once, verify it, and you never have to trust someone else's rip again.