Howto: Egg Scripts
http://www.pokecommunity.com/showthread.php?t=67801
I never actually thought someone would manage to find out how, but Sergio–, the person responsible for the excellent “Pokémon Naranja”, has found it. It’s probably been lurking around the more advanced ROM hackers though (but I certainly didn’t catch wind of it).
… Maybe it goes around the German ROM hackers a lot more.
Originally posted on the old Rijon website, now offline. Archive link. The PokéCommunity thread this post linked to no longer exists, and unfortunately there appears to be no archive of it.
