Tutorial: apply an IPS or BPS patch to a ROM in your browser (Rom Patcher JS)

ROM hacks and fan translations are almost never distributed as full games: you get a small patch file (.ips, .bps, .ups, .ppf, .xdelta...) that you apply to your own ROM. This guide, checked on 11/11/2026, uses Rom Patcher JS (version 3.5 by Marc Robledo), which runs in your browser: nothing to install.

Before you start

You need: (1) a ROM of the original game that you legally own, in the exact version the patch author asks for (region, revision); (2) the patch file, downloaded from the author's page (often ROMhacking.net or GitHub). ROMs are never bundled with patches and we do not link to any. Always keep your original ROM: the patch creates a new file. If your ROM is inside a .zip, the tool can unzip it for you.

1. Open Rom Patcher JS in your browser.
2. In the "ROM" area, load your game file. The tool shows its CRC32, MD5 and SHA-1 checksums: compare them with those listed by the patch author. If they differ, your ROM is not the right version and the result may not work.
3. In the "Patch" area, load the .ips, .bps, .ups, .ppf or other file.
4. Leave "Fix ROM checksum" ticked unless the author says otherwise, then click "Apply patch".
5. Your browser downloads the modified ROM. The "Use patch name for output" option names it after the patch, handy to avoid overwriting the original.
6. Launch the new file in your emulator (RetroArch, for example), or copy it to your flashcart or handheld.

If it does not work

First reflex: recheck the ROM checksums, then the region and revision requested. Some patches require a headerless ROM: the project's GitHub repository says the tool can strip headers before patching. It also handles IPS, BPS, UPS, APS, RUP, PPF, EBP, BSDiff and xdelta. A desktop alternative is Floating IPS (Flips), whose original repository has been archived since May 2025; its last release, v198, is still available on the Sir-Walrus fork. To play with achievements afterwards, see our RetroAchievements tutorial for RetroArch.

Source: Rom Patcher JS