AreaDex/GS:08703 (0x21FF)
Map 21FF is a glitch map in Generation II. As its name suggests, its index number is 21FF. In the English version of Pokémon Gold/Silver it does not freeze the game, but it freezes the game in the Japanese version and in Pokémon Crystal, where the layout of the map is probably different.
Accessing map 21FF
Map 21FF can be accessed when entering a door with the codes 012144D0 and 01FF45D0 activated, but it cannot be explored without the following walk through walls codes: 0108A3CE, 0108A4CE, 0108A5CE, 0108A6CE. The map is long, but very narrow.
Properties
According to the Pokégear, map 21FF may be in Blackthorn City or Goldenrod City.[citation needed]
No music (track 00 according to memory address C1A9) plays in the map. The map is very narrow, only being two tiles thick but it is actually long. If the player steps out of bounds they may get a Glitch Dimension or actually be taken to another map (which has the Route 27 music playing).
When the room is first entered it will appear pitch-black except for its two tile wide path which is mainly white. 'Yellow dot pattern' tiles can be seen in the room.
The player can use Flash to brighten up the room. The room appears to use a tileset based on the Ruins of Alph (perhaps it is that tileset) as Unown markings can be seen.
Though Flash can be used to light the area up, like in a cave, neither Dig or Teleport can be used to escape from the map. Fly cannot be used to escape from the map either.
Even after using the above walk through walls code, the player cannot walk through certain positions on the map from all directions.