Video Summary - You can play Gen 3 Pokemon ONLINE with ANY DEVICE (yes, even that one)

Summary of Technological Concepts, Features, and How-To Details

Problem Being Solved

Even though Gen 3 Pokémon (GBA) games run on modern hardware with internet, the original multiplayer design assumed local connection—either:

physical link cables, or
limited proprietary wireless adapters.

As a result, multiplayer typically required players to be in the same room.

Core Solution: GB Link

GB Link is a community project that enables Gen 3 multiplayer online by bridging GBA link-cable communication to internet-connected devices/emulators.

It’s described as more than a simple adapter—it includes both:

software, and
hardware

so different devices can participate in the same “link” session.

How It Works (Technical Approach)

Why Online Is Hard for Link Cable Protocols

Real-world networking issues break typical link-cable assumptions:

latency
packet loss
unstable Wi‑Fi

Key Insight: Turn-Based Networking Compatibility

Pokémon multiplayer is turn-based, and the game’s communication protocol expects a “wait/receive” style of behavior. That makes it possible to emulate a stable cable-like experience over the internet.

Reverse Engineering

Developer SO Meter performed significant reverse engineering of the GBA communication cable protocol, then created Celio Link—game-specific software for Pokémon.

Simplified Synchronization Strategy

From the described “subtitles” approach:

Celio Link constantly sends commands so the GBA believes everything is functioning normally.
Incoming internet multiplayer data is packaged and transmitted using the cable protocol in a way that matches what the game expects.

Not Just Pokémon

The same overall approach is also mentioned for Advance Wars.

RetroArch / GPSP Integration

GPSP RetroArch Kernel Updates

Game-specific netplay settings were added to the GPSP RetroArch kernel, enabling emulator-to-emulator multiplayer using the same multiplayer backend.

Cross-Device Emulator Support

RetroArch is described as usable across many platforms, including:

iPhone
Android
PC
macOS
Linux
handheld emulation consoles

Hardware Bridging (USB ↔ GBA Link Cable)

After solving the software side, the team built adapters to physically connect a GBA link cable to USB.

Example DIY Reference

An earlier community adapter used a Raspberry Pi Pico, demonstrated by Stack Smashing.

Product Highlight

GB Link V2 (by Starlark) is highlighted for:

a smaller form factor
a convenient cable connector
packaging in a clear case

It was sold via Crowd Supply, with the campaign described as already fully funded (not “pay and pray”; production/batch underway).

Connecting Beyond “GBA + Emulators”: Switch Support via ESP32

Switch Multiplayer Limitation

Official Switch ports are described as local wireless only, with no built-in online play.

Workaround Using an ESP32

The project uses an ESP32 microcontroller (about $10) with built-in Wi‑Fi/Bluetooth.

The workflow includes:

Installing firmware that allows ESP32 to communicate using the Switch wireless protocol.
Handling an important limitation: Switch communication is encrypted.

Encryption Caveat (Prod Keys)

To work with the encrypted protocol, you need proprietary prod.keys, supplied via a key-file process (not publicly linked).

The subtitle claims keys can be extracted using RCM’s Lockpick, and references switch.hacks.guide for homebrew instructions.

Claimed Result

After firmware + keys, Switch (including mentions of Switch 1 / Switch Two) can join Celio Link, enabling online:

trading
battling

with combinations including:

real GBA hardware
GBA emulators
another Switch

Tutorial-Style Setup Walkthrough (User Configuration)

1) Easiest Path: RetroArch-to-RetroArch Netplay

On two devices running RetroArch:

Enable Netplay options, including:
- public announcement
- relay server usage
Host device sets a server password (example: "1234").
Joining device uses the netplay host list/lobby (example host name: "Jeff phone").

For Pokémon:

RetroArch kernel options include a “Gen 3 mode” tailored to this cable-link multiplayer approach.

Additional mentioned tip:

Save conversion between different 3DS/GBA methods:
- rename save extension .sav ↔ .srm
Example flow: run Pokémon Emerald in emulator, connect, and start a battle.

2) Celio Link “Browser/Code” Flow (Phone as a Bridge, No PC)

This flow uses:

the Celio Link website (celio.gblink.io)
a GB Link USB adapter connected to a phone

Steps described:

Create a lobby in the browser UI.
Receive a 4-digit session code (example: "2946").
On the other end, use mGBA Celio edition (explicitly stated as supported).
Download/open celio_server.lua in the mGBA “tools/scripts” flow.
Enter the session code to join.
Start communication and initiate multiplayer from within the Pokémon game.

3) GB Link Netplay Bridge for RetroArch (“GBA ↔ Emulator Clients”)

A desktop application from GB Link helps connect:

a physical/real GBA using GB Link
to players using RetroArch netplay

Demonstrated behavior:

host mode + relay server enabled
password example: "1234"
other devices join and begin a Pokémon battle (example: “Colosseum” single battle)

Testing / Limitations Noted

Switch ↔ RetroArch Bridge Not Fully Ready

The subtitle states:

GB Link Netplay bridge cannot yet communicate with ESP32-based Switch connections, but it’s listed as a dev to-do item.

Crash During Battle Testing

They report a crash during testing (example Pokémon: “Blissey”).
The developer was contacted and is working on it.

Trade vs Battle Stability

Subtitles emphasize:

Trading works well (example mentions oddish/porygon).
Online sharing works well.
Battles are still being stabilized.

Community / Review-Style Information

Sponsorship

The video creator states the project is not sponsored.

Additional GB Link Features Mentioned

Beyond multiplayer:

save backups
event mailings
“miracle exchange”
Gameboy Printer
e-Reader
community events such as tournaments, swaps, and secret base exchanges

Where to Get Help

The video recommends joining GB Link Discord to:

get help
find players

Main Speakers / Sources

SO Meter — creator of Celio Link; lead developer; referenced as uploading an August 2025 YouTube video showing an internet-connected GBA setup.
Starlark — GB Link team developer; associated with adapters and GB Link V2 hardware.
David GF — developer of the GPSP RetroArch kernel; implemented game-specific network play settings in Oct 2025.
Video narrator / creator — person demonstrating setup steps and testing (no specific name provided in subtitles).

You can play Gen 3 Pokemon ONLINE with ANY DEVICE (yes, even that one)

Key takeaways