Sonic CD v1.2.1 by Voxel9
Sonic CD on the 3DS through the Retro Engine v3 decompilation, using your own game files
Install on your 3DS
Method 1Scan the QR code
With FBI (Remote Install › Scan QR Code) or 3dsDL (Scan QR Code). Either one installs it.
Method 2Send it to your 3DS
Open 3dsDL › Receive on the same Wi-Fi, then press:
Send to 3dsDL Not working?
Other ways to install
From your SD card: copy SonicCD.3dsx into /3ds/ and start it from the Homebrew Launcher.
Send can't find your 3DS? Type the address 3dsDL shows on Receive, then press Send.
Send to 3dsDL
Files
Screenshots
About Sonic CD
It won't run without the data from an official release of Sonic CD, from Steam, Sonic Origins, Android or iOS. Data.rsdk from the mobile version works best. Copy it to /3ds/SonicCD/. Audio needs a DSP firmware dump, which Luma3DS 10.3 or newer can do from the Rosalina menu under Misc options.
For mods, copy the decompiled RSDKv3 scripts to /3ds/SonicCD/Scripts/, set TxtScripts to true in settings.ini, and put the mod folders in /3ds/SonicCD/mods/. Cutscene videos only work from the original Steam release. Copy its videos folder over and shrink the OGV files to 400x240 with ffmpeg, as they're slow on an Old 3DS and choppy on a New one.
Hardware rendering is the default, with stereo 3D. A software renderer is there too, but it's slow on an Old 3DS and in the special stages on a New 3DS. Keys can be remapped in settings.ini, and Select opens the dev menu at any time. Voxel9 did the port, on top of the decompilation by Rubberduckycooly and others.
For mods, copy the decompiled RSDKv3 scripts to /3ds/SonicCD/Scripts/, set TxtScripts to true in settings.ini, and put the mod folders in /3ds/SonicCD/mods/. Cutscene videos only work from the original Steam release. Copy its videos folder over and shrink the OGV files to 400x240 with ffmpeg, as they're slow on an Old 3DS and choppy on a New one.
Hardware rendering is the default, with stereo 3D. A software renderer is there too, but it's slow on an Old 3DS and in the special stages on a New 3DS. Keys can be remapped in settings.ini, and Select opens the dev menu at any time. Voxel9 did the port, on top of the decompilation by Rubberduckycooly and others.
Release notes
v1.2.1 · Sep 21, 2026
v1.2.1
This is a minor update to the previous release which addresses the following:
- Fixes an issue where using the Data.rsdk of the PC version with hardware renderer enabled, then pausing and unpausing in any Tidal Tempest zone, would cause the entire screen to flash constantly.
- The fix has the added benefit of making Tidal Tempest visible with the PC Data.rsdk and HW renderer, however there are some slight visual errors, such as a lack of water discoloration and waterfalls not animating, but will not affect progression. To fix these errors, use the mobile Data.rsdk which, as a reminder, will also make the special stage floors draw correctly.
If you're upgrading from an older version (pre-1.2.0), delete the existing settings.ini to ensure stability.
Refer to the README for further instructions.