MissingNo HoF corruption
Posted by: Stackout
Date: 2014-03-28 16:35:27
Well, it's thanks to yet another buffer overflow, and that the sprite buffers are at the beginning of SRAM.
It tries to uncompress MissingNo's sprite, which is obviously not a compressed sprite (except in three well-known cases, you should be able to figure out which I mean hehe).
And it overflows the sprite buffer, and writes further into the save. The last sprite buffer ends at $A498, HoF data starts at $A598. (remove $A000 to get the offset in a .sav file)
This is probably the same reason why most if not all glitch Pokémon with invalid sprites cause HoF corruption.