gba lz77 compression — free browser tool | fatcousin

nintendo gba bios lz77 / lzss decompress + compress · swi 0x11 · 0x10 header · greedy match · rom-hacking tool · runs locally

mode

options

start offset (hex, optional — for mid-file LZ77 blocks)

drop file

drop a GBA LZ77-compressed file

.bin .lz .lz77 — must start with 0x10 (or set offset)

Select file

status

drop a file to compress or decompress

format reference

GBA LZ77 stream layout

byte 00x10 (magic)

bytes 1–3decompressed size (24-bit LE)

flag byte8 bits, MSB = first token type

bit = 0literal byte follows

bit = 12-byte backref: hi4 = len-3, lo12 = disp-1

match len3–18 bytes

displacement1–4096 bytes back

used in GBA games

Pokémon RSEtile maps, battle sprites

Fire Emblemall map data

Zelda: Minish Capgraphics, scripts

GBA BIOS SWI0x11 — LZ77UnCompWRAM