The logo is compressed using PB8, a form of RLE with unary-coded
run lengths. Each block representing 8 bytes consists of a control
byte, where each bit (MSB to LSB) is 0 for literal or 1 for repeat
previous, followed by the literals in that block.
PB8 compression is also used in a few NES games. A variant called
PB16, where 1 means repeat 2 bytes back, is used in the Game Boy
port of 240p Test Suite and in Libbet and the Magic Floor.
Switching from logo-compress RLE to PB8 decreases the compressed
logo data size from 287 bytes to 253 bytes, saving 34 bytes.
The decompression code is also about 10 bytes smaller.
Lior Halphon