N64 ROM formats

File extensions

Extension	Usual byte order	Notes
.n64	Byte-swapped	Previously used by No-Intro
.n64	Little-endian	Very rare
.v64	Byte-swapped	Named after the Doctor V64 backup device
.z64	Native	Named after the Z64 backup device

Note that the actual byte order of a ROM may not always be the one expected from its file extension.

Byte orders

Format	Order	Header (hex)	Example string
Native	ABCD	80 37 12 40	SUPER␣MARIO␣64␣␣
Byte-swapped	BADC	37 80 40 12	USEP␣RAMIR␣O46␣␣
Little-endian (rare)	DCBA	40 12 37 80	EPUSAM␣R␣OIR␣␣46