Unlocking Tsunekazu Ishihara's team in Pokémon Red (pokered)

Continuing on from the modifications made to pokered in the previous post, I noticed an interesting unused behaviour in the assembly code. It looked to be an unused debug function which gives the player Tsunekazu Ishihara’s favourite Pokémon. In this post I will document making this function accessible by talking to Mom in Pallet Town.

As most of the assembly code was already present to add this behaviour, all that was required was to update scripts/RedsHouse1F.asm like so.

RedsHouse1FText1: ; Mom
  TX_ASM
  ld a, [wd72e]
  bit 3, a
- jr nz, .heal ; if player has received a Pokémon from Oak, heal team
  ld hl, MomWakeUpText
  call PrintText
+ callba SetIshiharaTeam
  jr .done

So now, instead of healing any present Pokémon, Mom will instead provide us with Ishihara’s team. To document this change to the player I updated the text that was presented when talking to Mom within text/maps/RedsHouse1F.asm.

_MomWakeUpText::
  text "MOM: Right."
  line "All boys leave"
  cont "home some day."
  cont "It said so on TV."

- para "PROF.OAK, next"
- line "door, is looking"
- cont "for you."
+ para "Have Ishihara's"
+ line "favourite #MON"
+ cont ""
  done

After compiling and booting up the ROM, we can now see the new behaviour in action. 🎉