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Pokemon Crystal - 251

Hack of Pokémon: Crystal Version


Pokémon Crystal: 251 is a vanilla Pokémon Crystal hack which allows players to catch all 251 monsters and collect all the special items without the need for a game-link cable. While this was specifically created for play on emulators, it is considerate of players who would like to flash the rom to real cartridges for use on real hardware, and changes nothing which might create incompatibilities. The patch DOES NOT make any attempt at changing or introducing any new evolution methods, sprites, monsters, attacks, difficulties, settings, features, etc… This patch is purely focused on playing through the classic Crystal with organic solutions to not having game-link abilities.

Spoiler-Free Description…

Bugs and Glitches

  • Most bugs and glitches from Pokémon Crystal have been fixed, notably:
  • Moon, Love, Fast and Heavy Balls now work correctly
  • Daisy’s Grooming now appropriately increases happiness
  • BURN, POISON and PARALYSIS now actually affect catch rate
  • Magikarp are now properly measured, and are the correct size at Lake of Rage
  • Glacier Badge boost now works as intended
  • Dragon Fang (not Dragon Scale) now correctly boosts Dragon-Type moves
  • Plus more (see readme)


  • Very little text has been changed - only where it was needed.
  • The Game Developer’s computer in Celadon shows which patch version is in use (currently v2.0), instead of saying not to mess with the game program.


  • All Mystery Gift and Time Capsule exclusive items, including hold items and room decorations, are all obtainable in-game now (v2.0)!


  • A single “patch” of flowers has been added outside Elm’s Lab to indicate a successful software “patch.”
  • A few new areas have been developed, based off of RBYG or alpha/beta references, purely for organic solutions to some of the “missing from Crystal” Pokémon and items.


  • Celebi can be obtained via the fully functioning GS Ball Event.
  • Missing Legendary Pokémon are waiting to be battled.
  • Somehow you will come across one of each of the trade-evolution Pokémon.
  • Missing Pokémon who’ve been re-introduced into the wild take their cues from Gold, Silver, Yellow, Red, Blue, and Green
  • Pokémon new to the wild have had considerable thought put into rarity, environment, and balancing
  • Ho-oh and Lugia both now have their signature attacks which were only available in Gold and Silver.
  • Four unique event Pokémon have been added to replicate the special Pokémon which were originally obtained via Pokémon Stadium 1 & 2.


  • All have been altered in some way, and all are important.
  • There is a new character who can help players remember where these trades are located, and what is on offer (see image).


  • The three music tracks exclusive to the Japanese mobile adaptor functionality have been added to one specific location each.
  • All unused NPC emotes and an unused NPC sprite and NPC color palette have been added in at least one location each.

For a more detailed (spoiler) look at all Pokémon and item locations and changes, check the README file.

  • For players who have emulators which accurately keep track of time, or are wishing to flash this patch to a cart which has a battery, there are no extra steps to take. For players who wish to play on emulators which have inaccurate or no time-keeping abilities, it is recommended to patch Crystal 251 with an RTC changer patch (a few are available here on RHDN), I have fully tested and can confirm complete compatibility with Drenn’s patch (run Crystal 251 patch first, then the RTC patch):
  • For players who will play on real hardware: All precautions have been taken to ensure that you can link up with all original games and have complete compatibility: GSC, RBY, Pokémon Stadium 1&2, Gameboy Printer, etc. In most cases, if a player were to officially obtain a special Mystery Gift item, like say a Bulbasaur Doll room decoration, BEFORE triggering the new in-game event, the in-game event will recognize this, and skip over the event entirely so there will be no confusion. In a few instances, this will not happen, but will not create any issues; the game will simply say that the player has unlocked the new doll.

UPDATE v2.0 Substantial update. Old save files can be used, but be sure to save inside of a Pokémon Center before updating. Patch using a fresh Pokémon Crystal (Rev 1) rom.

ROM / ISO Information:

  • Database match: Pokemon - Crystal Version (USA, Europe) (Rev 1)
  • Database: No-Intro: Game Boy/Color (v. 20210227-015730)
  • File/ROM SHA-1: F2F52230B536214EF7C9924F483392993E226CFB
  • File/ROM CRC32: 3358E30A




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User Review Information

User Reviews
A Dream come trueAizumi10 Jun 20221.1Yes
Brilliant HackKevCfcNo123 Apr 20221.1Yes