BPS Super Mario Bros. 2 Patcher vs ROM Patcher

BPS Super Mario Bros. 2 Patcher is a free web page for applying a BPS patch to a Super Mario Bros. 2 ROM. It provides separate upload controls for an SMB2 ROM and a BPS patch, then an Apply patch button. The page validates both files and shows invalid-file messages when they are rejected. It supports only the NTSC version; the page says an invalid ROM may be a bad dump or the wrong region. During validation, the code checks iNES 1.0 and iNES 2.0 headers and can swap them as needed. It recognizes ROM and patch checksums for revisions 0 and A, and can apply a revision conversion patch. After patching, the script saves a .nes file named from the patch filename. The project links to GitHub source code containing BPS handling, ROM and hash code, revision patches, scripts and styles. The page credits Marc Robledo for Rom patcher JS.

ROM Patcher is a free browser tool that applies patch files to a user's legally dumped game backup and produces a modified ROM. Common uses include fan translations, bug fixes and ROM hacks. It supports IPS, UPS, BPS, xdelta, APS, PPF and RUP formats, and the site includes a Pokémon-focused patching guide. No installation or account is needed. ROM and patch files are processed in the browser rather than uploaded, stored or transmitted by the service; the resulting ROM is generated there and offered as a local download. Patching runs in a Web Worker so the page does not freeze when handling large ROM files. The site does not provide ROMs, so users need to supply their own legally dumped backups. Verification differs by format: UPS checks source and result ROMs with CRC32, while BPS checks the source, target and patch. IPS is limited to files smaller than approximately 16 MB and has no built-in checksum, so using the wrong ROM can silently corrupt it. The patched output can be loaded in an emulator of the user's choice. The maker describes the rest of the site as an early, growing preview.