ROM Hacks are a great way to enjoy classic games in a new way. ROM Hacks can add new levels to your favorite platformer, add a brand new story to your favorite RPG, or even change the game into something new entirely. But ROM Hacks are typically distributed via patch files. Patch files can end in a variety of different extensions including but not limited to: .IPS .UPS .APS or .BPS. Patch files are not playable by themselves in emulators such as Afterplay.io. Instead they must be applied to the ROM file of the game that they were created for, generating a brand new ROM file. This processes is known as “patching”. Luckily there are tools on the web that allow us to do this patching process all from just an iPhone or iPad. Follow this guide for a step-by-step tutorial on how to patch a ROM on your phone to use on an emulator such as Afterplay.

To prepare for this guide, download the ROM you wish to patch and the patch file to a folder on your phone. (Check out my previous blog post on some ways to legally dump your game collection to ROMs). In this guide, I patch Pokemon Emerald to become the Pokemon Exceeded 9.0 ROM Hack, but these same steps should apply to any game, hack, or system.

Step 1. Patching the ROM

  • Open Rom Patcher Js by Marc Robledo. https://www.marcrobledo.com/RomPatcher.js/

  • Upload your base ROM by tapping “Choose File” next to “ROM file:” and then “Choose File” in the drop down menu. Find your base ROM (in my case Pokemon Emerald.gba) from the file picker. You may need tap back a few times to find the location where the ROM is saved. The default location for files saved from the internet via Safari is “iCloud Drive -> Downloads”

  • Upload your patch file by tapping “Choose File” next to “Patch file:” and then “Choose File” in the drop down menu. Find your patch file (in my case PokemonExceeded9.0.ups) in the picker. Again, you may need to tap back a few times until you find the location where the patch file is saved.

  • Note: You may get a Source ROM checksum mismatch error. This may indicate that the patch was created using a different revision of the game than your base ROM. This doesn’t always mean incompatibility though. Go ahead and tap “Apply Patch” in the next step and give it a try. We can troubleshoot later

  • Tap “Apply Patch”. The website will patch your ROM with the uploaded patch file and then give you a pop up to download the resulting hacked ROM. Tap “Download” and wait for the download indicator in the bottom left of the address bar to indicate the ROM hack is finished downloading

Step 2. Uploading the ROM to Afterplay

  • Switch to the Afterplay app. Once Afterplay has finished loading, tap the Afterplay menu (top left) and tap the “Add Game” button.

  • Choose your console, and then upload your patched ROM by tapping “Select File” and then “Choose File” from the drop down. Find your patched ROM. It should be the name of the source ROM with (patched) appended to it. In my case Pokemon Emerald (patched).gba. You may need to tap back a few times to find the patched ROM. By default, ROM Patcher Js should have saved it under “iCloud Drive -> Downloads” but this may be different depending on your browser or settings.

  • Tap “Play” to start enjoying or tap “Go to Library” to view the ROM hack in your library and to edit the ROM hacks name and box art.

Step 3. Name your ROM Hack and test it out

  • Tap the Afterplay menu (top left) and choose “Recently Added”. Your newly added ROM Hack should be at the top of the list with the name of the Base ROM with (patched) added at the end. (In my case Pokemon Emerald (patched))

  • Tap the 3 vertical dots in the top right of the title card box for your ROM hack, then tap “Edit”.

  • Give your ROM Hack the proper name, and add an image to use for box art if you wish. Changes save automatically so just tap the “X” when finished naming and adding box art.

  • Tap the title card box for your ROM hack to load it and start testing it. If all went correctly everything should load in 5 seconds or less.

Troubleshooting Tips

If the patcher refreshes in the middle of the process, close out of some open tabs and apps and try the process from step 1 again. If you have any Safari extensions installed, temporarily disable them while using the patcher.

If the source ROM mismatch error comes up, you may be dealing with a game that is built off a different version of the game than the version your ROM is. Or it could be a patch from what is known as an “extended ROM”. This is common with ROM hacks from certain games. Radical Red is a popular case of this. Radical Red is built off of an extended version of FireRed. So you would need to modify your FireRed ROM to the extended version prior to patching it to “Radical Red”. This is out of the scope of this guide, but Google is your friend in that regard.

If you have any questions, drop a comment below and I will try to help you out and add it to the section above. Good luck and have fun enjoying these new twists on old favorites.