Troubleshooting

Common problems and how to solve them. If your case isn't here, reach out via the contact form on the web.

The dongle won't power on

• Check the battery is correctly seated (polarity).
• Confirm the battery is a rechargeable Li-ion 3.7V cell in 16340 or 18350 format (not the primary 3V CR123A).
• Plug in the USB-C cable: if it's charging you should see the lightning bolt icon on the OLED.
• If the dongle shut down due to inactivity, press the button briefly to wake it in Multiboot.

OLED is invisible / flickers

• If it flickers when plugging USB, check the cable and power supply. Outside flashing or an update, you can shut down by holding the button for 3 seconds, release it, then press briefly to power on again.
• If it never displays anything, check the screen isn't physically damaged.

The GBA does not receive the menu

• Make sure the Link cable is properly seated on both ends.
• Start the GBA holding Select + Start until the Game Boy logo stays still.
• Leave the dongle in Multiboot. Short presses cycle through Multiboot → GBA → Online → Multiboot; transfer starts automatically when a ready GBA is detected.
• A cartridge is not needed to receive the menu. See Getting started for the complete procedure.

Wi-Fi won't connect or drops

• Check from the GBA itself (Settings → Wi-Fi) that you can see your network.
• Verify the password.
• If your network is 5 GHz only, the dongle won't see it: the ESP32 only supports 2.4 GHz.
• If it connects but drops mid-download, try moving the dongle closer to the router.

The game does not connect in Online mode

• Check that the game uses the CanoFlash SDK and that Wi-Fi has Internet access.
• You can select Online with the button before pressing Connect in the game. The SDK handshake is also detected from GBA and Multiboot.
• Changing modes keeps Wi-Fi on. Pressing the button while in Online closes the session and returns to Multiboot; do not use it to refresh a running match.
• If the dongle shut down due to inactivity, wake it with a short press and reconnect from the game.
• For API key, room or reconnection errors, see the SDK troubleshooting guide.

Cartridge verification fails

• Make sure the cartridge has the supported chip (AMD/Spansion S29GL256).
• Clean the cartridge contacts with a cotton swab and isopropyl alcohol.
• Retry the download: a momentary bad contact can break verification.

Cartridge not recognized

• The dongle shows the chip ID it reads. If it doesn't match 0x227E, that cartridge is not supported.
• Cartridges with Macronix, Sharp or other chips are not currently supported.

My save doesn't show up in the cloud

• Confirm you have uploaded the save from Save Manager on the GBA, not just saved on the cartridge.
• Refresh the Saves tab on the web.
• Check Wi-Fi and retry the upload from the GBA. Authentication renews automatically; changing mode with the button does not force a renewal.

How to recover a dongle that won't authenticate

If the web tells you the dongle isn't authenticated:

1. Check that the device serial number (CFX-XXXXXX) matches the device linked in your panel.
2. If you have updated the firmware, check the Wi-Fi connection and use the official recovery procedure if the problem persists.
3. To restart, hold the button for at least 3 seconds to shut down, release it, then press briefly to power on. This keeps your configuration; it is not a factory reset.