gba huffman decompressor — free browser tool | fatcousin

nintendo gba bios huffman decompress · swi 0x13 · 4-bit and 8-bit symbol modes · 0x20 / 0x28 header · rom-hacking tool · runs locally

drop file

drop a GBA Huffman-compressed file

.bin — must start with 0x20 (4-bit symbols) or 0x28 (8-bit symbols)

Select file

status

drop a GBA Huffman-compressed binary

format reference

GBA Huffman header layout

byte 00x20 (4-bit) or 0x28 (8-bit)

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

byte 4(tree_node_count - 1) / 2

treebinary Huffman tree nodes

data32-bit LE words, MSB-first

BIOS SWI0x13 — HuffUnComp

usage note

compressornot included — very rare in ROM hacking

common usebackground tiles, compressed data blobs

detectionlook for 0x20 or 0x28 at known offsets

often pairedLZ77 first, then Huffman inner layer