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remove trailing padding bytes from rom files · nes iNES exact size · trim 0xFF · trim 0x00 · runs locally

drop a rom file
.nes · .sfc · .gba · .gb · .gbc · .md · any binary
drop a rom to analyse its trailing padding

GBA roms are commonly padded with 0xFF bytes to a power-of-two size by ROM set tools. Trimming removes this padding and is safe — GBA hardware and emulators ignore trailing bytes past the cartridge size.

NES roms (iNES format) have exact content sizes encoded in the header (PRG and CHR page counts). This tool trims to the exact size implied by the header.

0xFF trimming is safe for GBA, GB, GBC, NES, SNES ROMs that have been padded. The trimmed ROM plays identically.

0x00 trimming is less common — only trim 0x00 if you are confident the trailing null bytes are padding and not actual ROM data.

you supply your own files. fatcousin does not host, link to, or recommend sources for rom files, bios files, or copyrighted game data. this tool is for preservation, modding, research, and education with files you lawfully possess. all processing runs in your browser — files never leave your device.

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