pokegold/docs/bugs_and_glitches.md

Bugs and Glitches

These are known bugs and glitches in the original Pokémon Gold and Silver games: code that clearly does not work as intended, or that only works in limited circumstances but has the possibility to fail or crash.

Fixes are written in the diff format. If you've used Git before, this should look familiar:

 this is some code
-delete red - lines
+add green + lines

All the bugs documented here were fixed in Pokémon Crystal. Any that weren't are already documented in the pokecrystal repo, so they're not duplicated here.

Contents

• Using the Coin Case can cause arbitrary code execution
• Entering the Hall of Fame without a save file can corrupt the PC boxes
• The Lucky Number Show does not find winning ID numbers in inactive boxes 10-14
• Present's text overflows when it fails to heal an enemy Pokémon with a long name
• You can Surf on top of NPCs
• You can fish in the water in Cerulean Gym
• "Route 15" is not capitalized in a signpost

Using the Coin Case can cause arbitrary code execution

(Videos)

Fix: Edit _CoinCaseCountText in data/text/common_3.asm:

 _CoinCaseCountText::
-; BUG: Using the Coin Case can cause arbitrary code execution (see docs/bugs_and_glitches.md)
 	text "Coins:"
 	line "@"
 	text_decimal wCoins, 2, 4
-	done
+	text_end

Entering the Hall of Fame without a save file can corrupt the PC boxes

(Video)

Fix: Edit HallOfFame in engine/events/halloffame.asm:

-; BUG: Entering the Hall of Fame without a save file can corrupt the PC boxes (see docs/bugs_and_glitches.md)

+	ld a, [wSavedAtLeastOnce]
+	and a
+	jr nz, .saved
+	farcall ErasePreviousSave
+.saved

The Lucky Number Show does not find winning ID numbers in inactive boxes 10-14

Fix: Edit CheckForLuckyNumberWinners in engine/events/lucky_number.asm:

-	; BUG: The Lucky Number Show does not find winning ID numbers in inactive boxes 10-14 (see docs/bugs_and_glitches.md)
-	cp NUM_BOXES_JP
+	cp NUM_BOXES
 	jr c, .BoxesLoop

Present's text overflows when it fails to heal an enemy Pokémon with a long name

Fix: Edit PresentFailedText in data/text/battle.asm:

 PresentFailedText:
-; BUG: Present's text overflows when it fails to heal an enemy Pokémon with a long name (see docs/bugs_and_glitches.md)
-	text "<TARGET> can't"
-	line "receive the gift!"
+	text "<TARGET>"
+	line "refused the gift!"
 	prompt

You can Surf on top of NPCs

Fix: Edit SurfFunction in engine/events/overworld.asm:

 .TrySurf:
-; BUG: You can Surf on top of NPCs (see docs/bugs_and_glitches.md)
 	ld de, ENGINE_FOGBADGE
 	call CheckBadge
 	jr c, .nofogbadge
 	ld hl, wBikeFlags
 	bit BIKEFLAGS_ALWAYS_ON_BIKE_F, [hl]
 	jr nz, .cannotsurf
 	ld a, [wPlayerState]
 	cp PLAYER_SURF
 	jr z, .alreadyfail
 	cp PLAYER_SURF_PIKA
 	jr z, .alreadyfail
 	call GetFacingTileCoord
 	call GetTilePermission
 	cp WATER_TILE
 	jr nz, .cannotsurf
 	call CheckDirection
 	jr c, .cannotsurf
+	farcall CheckFacingObject
+	jr c, .cannotsurf
 	ld a, $1
 	ret

You can fish in the water in Cerulean Gym

Fix: Edit MapGroup_Cerulean in data/maps/maps.asm:

-; BUG: You can fish in the water in Cerulean Gym (see docs/bugs_and_glitches.md)
-	map CeruleanGym, TILESET_PORT, INDOOR, LANDMARK_CERULEAN_CITY, MUSIC_GYM, TRUE, PALETTE_DAY, FISHGROUP_SHORE
+	map CeruleanGym, TILESET_PORT, INDOOR, LANDMARK_CERULEAN_CITY, MUSIC_GYM, TRUE, PALETTE_DAY, FISHGROUP_NONE

"Route 15" is not capitalized in a signpost

Fix: Edit Route15SignText in maps/Route15.asm:

 Route15SignText:
-; BUG: "Route 15" is not capitalized in a signpost (see docs/bugs_and_glitches.md)
-	text "Route 15"
+	text "ROUTE 15"

	para "FUCHSIA CITY -"
	line "LAVENDER TOWN"
	done

(There are many other text changes between Gold/Silver and Crystal, but they are more subjective edits, not definite corrections.)