How to Play Pokemon ROM Hacks on iPhone with Delta
Updated October 13, 2026 · 10 minutes
Overview
For years, playing a Pokemon ROM hack on an iPhone meant sideloading, expiring certificates or a jailbreak. That changed when Apple began allowing emulators and Delta — the successor to GBA4iOS — arrived as a free download. Today you can play Radical Red, Unbound, Renegade Platinum and almost any other hack on an iPhone or iPad with nothing more than Delta, the Files app and Safari.
Delta runs Game Boy, Game Boy Color, Game Boy Advance and Nintendo DS games, which covers every platform on this site. The one thing it does not do is apply patches, so the process has two parts: first turn the patch into a playable ROM in Safari, then import that ROM into Delta. The whole setup takes about ten minutes, and you only do it once per hack.
Step by Step
Install Delta
Outside the EU, search for Delta - Game Emulator in the App Store and install it; it is free. In EU countries Delta is distributed through AltStore PAL instead, so install AltStore PAL first and get Delta from there. No jailbreak or computer is needed in either case.
Save the patch and your base ROM in Files
Download the hack's patch (.ups, .bps, .ips or .xdelta) and put it in a folder in the Files app together with a clean copy of the base game from your own cartridge. If either file is inside a .zip, tap it once in Files and iOS will extract it automatically.
Patch the ROM in Safari
Open Rom Patcher JS in Safari. Tap ROM file and choose the base game, tap Patch file and choose the patch, then tap Apply patch. Safari saves the result to the Downloads folder in Files. If you get a checksum error, your base ROM is the wrong version — our patching guide explains how to fix it.
Rename the patched file
Delta only recognises games by extension. Long-press the patched file in Files, choose Rename and make sure it ends in .gba for GBA hacks, .gbc or .gb for Game Boy hacks, or .nds for DS hacks. A clear name like Unbound.gba also makes it easier to find later.
Import the game into Delta
Open Delta, tap the + button in the top-right corner (choose Files if Delta asks for a source). Browse to the patched ROM and select it. The game appears in your Delta library, and you can long-press it to change the artwork or open cheats and save states.
Add DS BIOS files (DS hacks only)
To run Nintendo DS hacks such as Renegade Platinum or Blaze Black 2 Redux, Delta needs three system files dumped from your own DS: bios7.bin, bios9.bin and firmware.bin. Open Delta's settings, go to the Nintendo DS section and import each file. Avoid downloading these from random sites — many are mislabelled or bundled with junk.
Turn on sync and start playing
In Delta's settings, enable sync with Google Drive or Dropbox so your in-game saves are backed up. Then launch the game and save normally inside it. Use save states for tricky battles, but rely on the in-game save for your real progress — it is the file you will need when the hack updates.
Troubleshooting
The file is greyed out when importing — the extension is wrong or the ROM is still zipped. Rename it to .gba, .gbc, .gb or .nds and import again.
The game boots to a white screen — the patch was applied to the wrong base ROM. Patch again with a clean copy and check the checksum in Rom Patcher JS against the hack's readme.
Progress disappeared after updating the hack — Delta stores saves per game. Before importing a new version, export the old save from the game's context menu, import the new ROM, then import the save into it. Check the update notes first; not every update keeps old saves working.
Performance drops in DS games — DS emulation is much heavier than GBA. Close background apps, disable Low Power Mode and avoid fast-forward on older iPhones.
Controllers, Skins and Cheats
Delta supports MFi, Xbox and PlayStation controllers over Bluetooth, which makes long hacks much more comfortable. You can also install custom controller skins if the default layout covers too much of the screen, and enter GameShark, Action Replay or Code Breaker cheats for GBA games from the in-game menu.
Be careful with cheats in hacks built on modern engines such as Radical Red or Unbound: many standard codes target vanilla memory addresses and can corrupt a save. Use codes made specifically for that hack, and back up your save first.
FAQ
Can I play Pokemon ROM hacks on iPhone without a jailbreak?
Yes. Delta is a free emulator from the App Store (or AltStore PAL in the EU), so you only need the app, the Files app and Safari.
Does Delta work with Radical Red and Unbound?
Yes. Patch the hack onto the correct FireRed ROM, rename the result to .gba and import it into Delta like any other game.
Can Delta patch ROM hacks by itself?
No. Delta does not apply patches, so you need to create the patched ROM first with a browser tool such as Rom Patcher JS in Safari.
Why won't my DS ROM hack run in Delta?
Delta needs the bios7.bin, bios9.bin and firmware.bin files from a Nintendo DS for DS games. Add them in the Nintendo DS section of Delta's settings.
Does Delta work on iPad?
Yes. Delta runs on iPhone and iPad, and the larger screen is especially nice for DS hacks.