BPS Super Mario Bros. 2 Patcher vs Rompatcher

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.

Rompatcher is a free ROM patching tool for Linux and Windows, written in Rust. It applies patches and detects their formats automatically from their magic bytes. The listed formats are IPS, BPS, UPS, APS N64, APS GBA, EBP, RUP, PPF, xdelta and BDF, covering patch workflows for systems including Game Boy, NES, SNES, Game Boy Advance, Nintendo 64, PlayStation and PSP.

Checksum verification is optional and supports CRC32, Adler32 and MD5. Rompatcher can look up ROM hashes for more than 15 consoles through RetroAchievements. The project describes its patch writes as transactional, using atomic writes and rollback if an error occurs. Without an output path, the command places a file in a patched/ directory, based on the ROM name with .patched and its extension. The README reports approximately 27 microseconds to patch a 1 MB ROM in IPS format. Installation instructions use Cargo to build from source, and the listed license is MIT OR Apache-2.0. The project page states no pricing or usage limits.