Delta Emulator Game Won't Load / White Screen / NDS Crash Fix iOS

Wrong file extension is the most common cause of a game failing to load

Delta reads specific file extensions per system. If the file has the wrong extension, Delta either silently fails or shows a blank library entry that crashes on tap.

Supported formats by system:

• Game Boy Advance: .gba
• Game Boy Color / Game Boy: .gbc or .gb
• Super Nintendo: .sfc or .smc
• NES: .nes
• Nintendo 64: .z64, .n64, or .v64 (little-endian .v64 is sometimes problematic — prefer .z64)
• Nintendo DS: .nds
• Sega Genesis: .md, .gen, or .bin

Delta does not support zipped archives (.zip, .7z). Unzip the ROM file first on your PC/Mac, then transfer the raw ROM to your iPhone and re-import it.

How to remove a broken game entry and reimport:

1. In the Delta library, long-press the game tile.
2. Tap Delete (this removes only the library entry — your original ROM file in iCloud Drive or Dropbox is not affected).
3. Transfer the correct unzipped ROM to iCloud Drive or Google Drive.
4. In Delta, tap the + button → choose Files → select the correctly-named ROM file.
5. Tap the newly imported game to test.

Nintendo DS games require three BIOS files — without them, NDS games show a white screen

Delta's NDS emulation (DeSmuME/melonDS core) needs the real DS firmware to boot most commercial games. These files are not included in Delta and must be dumped from your own Nintendo DS hardware. They are not legally redistributable.

Required files:

• bios7.bin — ARM7 BIOS, exactly 16,384 bytes
• bios9.bin — ARM9 BIOS, exactly 4,096 bytes
• firmware.bin — DS firmware, exactly 262,144 bytes

How to add them to Delta:

1. Place the three files in iCloud Drive or Dropbox so they are accessible from the Files app.
2. Open Delta → Settings (gear icon, top-left of the library screen).
3. Scroll down to the Nintendo DS section.
4. Tap each of the three BIOS file slots and select the matching file from the Files app.
5. A green checkmark appears when a valid file is loaded.
6. All three slots must show green checkmarks. Retry your NDS game.

Without all three files, Delta may show a white screen, a black screen, or a "missing firmware" alert for NDS games. GBA, SNES, NES, and N64 games are unaffected — they do not need BIOS files.

Outdated Delta versions can fail on newer iOS builds

Delta receives regular updates on the App Store that fix compatibility issues with new iOS versions. An older Delta build running on iOS 17 or 18 may crash on games that a current build handles correctly.

1. Open the App Store → tap your profile picture → scroll to Pending Updates.
2. Update Delta if an update is available.
3. Retry the game.

Game-specific compatibility

Not all games run perfectly in emulation. A small number of titles have known issues in Delta's emulation core (particularly some N64 titles and late-era NDS games). Check the official Delta compatibility notes at delta-emulator.app before concluding your setup is broken.

iOS version requirement: Delta requires iOS 14 or later. iOS 16 or later is recommended for the best stability. If you are on an older iOS version you cannot update, consider using an older Delta build from GitHub releases.

If a specific game crashes consistently even after updating Delta and verifying the ROM format, the imported game's metadata or save state may have become corrupt during a failed import.

Full clean reimport:

1. Long-press the problem game in the Delta library → tap Delete.
2. Confirm deletion (this removes the library entry and associated save states stored in Delta's container; your original ROM file in Files/iCloud is untouched).
3. Close Delta completely: swipe up from the home bar, swipe away the Delta preview card.
4. Reopen Delta and re-import the ROM via + → Files.
5. Do not load any save state on first launch — run from the title screen to confirm the game launches cleanly before restoring a save.

If the game still crashes after a clean reimport and format verification, the ROM file itself may be incomplete or corrupted. Verify the file size matches the known correct size for that game and re-dump it from the cartridge if possible.