GBA Completed Hack of FireRed

Pokemon Odyssey

Pokémon Odyssey trades Gyms for layered labyrinths, double battles, Etrian-style exploration, three modes, and a new FireRed story.

  • New region
  • New story
Status
Completed
Plays on
PC · Android · iPhone (emulator)
Base game
Pokémon FireRed
Version
4.0.3/4.1
Made by
PacoScarso

About Pokemon Odyssey

Layered labyrinths ruled by captains, Etrian-style gathering, and a double-battle campaign set Pokémon Odyssey apart from a typical FireRed journey. PacoScarso's completed English GBA hack tells a new story in a new region without Gym Leaders, an evil team, or an Elite Four. Choose Minun or Plusle as a starter, then explore with mining, naval exploration, FOEs, side quests, Wonder Trade, and store upgrades. Every included Pokémon is rebalanced with revised learnsets, regional Etrian Variants, shared experience, selectable difficulty modes, and a soundtrack built for the new adventure.

What's in it

  • Adds a new story and region.
  • Uses new sprites, tilesets, and other graphics.
  • Removes Gym Leaders, evil teams, and the Elite Four for an exploration-focused structure.
  • Rebalances every Pokémon.
  • Adds Etrian regional variants.
  • Uses shared experience.
  • Offers Minun and Plusle as starter Pokémon.
  • Includes the first three generations, their Generation 4 evolutions, and extras such as Farigiraf.
  • Gives included Pokémon new learnsets and buffs weaker ones.
  • Offers Picnic, Normal, and Hard modes in the prologue.
  • Adds mining and gathering points, naval exploration, FOEs, and store upgrades.
  • Adds side quests and a side-quest menu.
  • Adds Wonder Trade.
  • Gives trainer and wild Pokémon 31 IVs in every stat.
  • Removes battle EV gains; use Power Items or lower-priced Vitamins instead.
  • Lets you change Pokémon natures and abilities in-game.
  • Divides the labyrinth into layers, each blocked by a captain battle.
  • Adds moves from later generations.
  • Highlights Pokémon natures in menus.
  • Adds an EV and IV screen to the Start menu.
  • Lets the automatic stroke be toggled with the L button on a GBA emulator.
  • Makes battles double battles unless you have only one Pokémon.
  • Uses a soft level cap.
  • Prevents healing items in battle unless they are held items such as berries.
  • Adds a Prodigious Exchange system at the Talrega guild.
  • Uses Generation VI-style Exp. Share.
  • Makes TMs infinite-use.
  • Adds a new soundtrack.
◆ POKEPATCHED NOTES

Pokémon Odyssey is PacoScarso's completed, story-focused FireRed dungeon crawler, built around the Yggdrasil Labyrinth rather than a conventional Gym route. Its practical trade-off is emulator and save-version sensitivity: the creator recommends mGBA, and the expanded-bag release cannot use v4.0.3 saves.

Base ROM: Pokémon Fire Red (U) (Squirrels) - 1636 — a clean dump has CRC32 DD88761C.

Before you patch

  • Use the official UPS patch with a clean Pokémon Fire Red (U) (Squirrels) - 1636 ROM.
  • Use the latest mGBA. PacoScarso specifically warns that VisualBoyAdvance can freeze or crash because its emulation is not accurate enough.
  • Choose your version before starting. The current English listing is v4.1.1, the expanded-bag build. Its infinite bag capacity comes at the cost of compatibility with v4.0.3 saves.

Who it’s for

Odyssey is for players after a story-focused dungeon crawler on the FireRed engine. The creator describes it as a Pokémon, Made in Abyss and Etrian Odyssey crossover, but says familiarity with those series is not required.

The completed main route reaches the eighth stratum; the creator’s final-development update then moved into postgame work. That makes it a better fit for someone wanting a self-contained campaign than an unfinished beta.

Version history

  • v4.0 — the creator’s final-version announcement.
  • v4.0.2 — fixes for some freezes and glitches after trainer battles.
  • v4.1.1 — current English expanded-bag release; use v4.0.3 instead if preserving that version’s save compatibility matters.

If you liked it

Sources

Notes researched 2026-09-25 from the sources above.

Pokemon Odyssey: common questions

Is Pokémon Odyssey finished?
Yes. PacoScarso announced the final version after four years of development; the creator later marked the eighth stratum's main events complete and moved on to postgame work.
Which ROM does the patch need?
The creator specifies Pokémon Fire Red (U) (Squirrels) - 1636. Odyssey is a UPS patch, so start with that clean base ROM rather than a pre-patched game.
Which emulator should I use?
Use the latest mGBA. The creator says VisualBoyAdvance's less accurate emulation can cause random freezes or crashes.
Can I move a v4.0.3 save to the expanded-bag release?
No. The v4.1.x expanded-bag builds have infinite bag capacity but are not compatible with v4.0.3 saves; the official page keeps v4.0.3 available as the save-compatible option.

Screenshots

Pokemon Odyssey in-game screenshot 1Pokemon Odyssey in-game screenshot 2Pokemon Odyssey in-game screenshot 3Pokemon Odyssey in-game screenshot 4Pokemon Odyssey in-game screenshot 5Pokemon Odyssey in-game screenshot 6Pokemon Odyssey in-game screenshot 7Pokemon Odyssey in-game screenshot 8Pokemon Odyssey in-game screenshot 9Pokemon Odyssey in-game screenshot 10Pokemon Odyssey in-game screenshot 11Pokemon Odyssey in-game screenshot 12Pokemon Odyssey in-game screenshot 13

Not sure how to install it?

A step-by-step walkthrough for GBA ROM hacks: emulators, patching tools and our in-browser patcher.

Open the guide
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