Flycast Guide

Guide Author: MewLew

Supported ROM Formats

Flycast supports the following game formats:

  • SEGA Dreamcast Titles: .cdi, .gdi, .chd, .cue (includes Windows CE games)
  • SEGA NAOMI GD-ROM Titles: .7z, .zip, .dat/.lst, .chd
  • SEGA NAOMI 1 & 2 Titles: .zip, .7z, .dat/.lst
  • Sammy Atomiswave Titles: .zip, .7z

Note: Flycast does not support Hikaru or SEGA System SP games.


Installing Flycast on Xbox Dev Mode

  1. Prepare Files:
    • Get the Flycast .appx file (e.g., flycast_2.5.appx).
    • (Optional) Get a Dreamcast BIOS (dc_boot) file for better compatibility.
  2. Upload BIOS to USB (optional but recommended):
    • Create a Sega - Dreamcast games folder on your USB.
    • Place the BIOS file and Dreamcast games inside.
  3. Install Flycast:
    • Enable Xbox Device Portal in your Xbox Dev Mode settings.
    • On your PC, open a web browser and enter the Xbox Device Portal URL.
    • Go to My games & appsAdd.
    • Drag and drop the Flycast .appx file, click Next, then Start.
    • Once installed, click Done.
  4. Change App to Game Mode:
    • On Xbox, hover over Flycast → press SelectView Details.
    • Change it from App to Game.

Internal Storage Setup

Where to upload your ROMs:

  • Xbox Device Portal → File explorerLocalAppData\Flycast\LocalState
    • Create a games folder here.
    • Upload Dreamcast ROMs.
    • You can upload .zip files — the portal will prompt you to unzip.

For cheats, VMUs, etc.:

  • Upload to:
    • LocalAppData\Flycast\LocalState\Data

Initial Configuration

  1. Launch Flycast.
  2. Go to SettingsContent LocationAdd.
  3. Press Up on the D-pad → A → keep pressing A on .. (Parent Directory) until you see drives.
  4. Select the E:/ drive (USB)
  5. If using internal storage the default drive will be Q:/.
  6. Press BSelect Current Directory.

  • Transparent Sorting: Per Pixel
  • Automatic Frame Skipping: Leave default
  • Widescreen Mode: Enable if desired
  • Filtering: 16x
  • VSync: Enable if needed
  • Show FPS Counter / VMU in-game: Optional
  • Internal Resolution: Max for Series X; reduce on Series S for best performance