Wild Pokémon Catch Cheat in DEBUG mode - pret/pokecrystal GitHub Wiki

This code was made by Luna.

In engine/items/item_effects.asm, go to PokeBallEffect:

.room_in_party
	xor a
	ld [wWildMon], a
	ld a, [wCurItem]
	cp PARK_BALL
	call nz, ReturnToBattle_UseBall

	ld hl, wOptions
	res NO_TEXT_SCROLL, [hl]
	ld hl, ItemUsedText
	call PrintText

	ld a, [wEnemyMonCatchRate]
	ld b, a
	ld a, [wBattleType]
	cp BATTLETYPE_TUTORIAL
	jp z, .catch_without_fail
+IF DEF(_DEBUG)
+	; Hold B + Down cheat in Debug Mode
+	call GetJoypad
+	ld a, [hJoyDown]
+	and D_DOWN + B_BUTTON
+	cp D_DOWN + B_BUTTON
+	jp z, .catch_without_fail
+ENDC
	ld a, [wCurItem]
	cp MASTER_BALL
	jp z, .catch_without_fail
	ld a, [wCurItem]
	ld c, a
	ld hl, BallMultiplierFunctionTable

Adding the code above essentially makes you jump to the .catch_without_fail label (like the Master Ball does) when you press B + Down simultaneously, allowing you to immediately capture wild Pokémon with any ball.