Evie (ChickasaurusGL) 🌺 | Starter Pokédex entries owned Ivysaur oversight and a few relevant ACE exploits (Generation I) @ChickasaurusGL | Uploaded December 2023 | Updated October 2024, 3 hours ago.
As documented in the Pokémon Red disassembly project and The Cutting Room Floor, when you view one of Professor Oak's three starters it temporarily marks Bulbasaur, Charmander and Squirtle as owned (as expected), before unsetting those flags. However, curiously Ivysaur is also marked as owned.
The player is also not expected to view the Pokédex list at this point, but if they did they would find those Pokémon as owned but not seen (unless they had already seen them). If the player views the Pokédex after the code unsets the own flags (i.e. backs out with B after viewing but not choosing the starter), any of the previous own entries before viewing the starters will also be disabled; so if you caught a Bulbasaur, Charmander, Squirtle or Ivysaur before viewing one of Professor Oak's Pokémon, this is a way of resetting all the entries again while retaining the seen flags.
In this video, I use arbitrary code execution to set up OAM DMA hijacking after the top-left border tile of the Pokédex entry is loaded into memory and partially save the game (using SaveSAVtoSRAM2; the function at pointer 780F in bank 0x1C), while freezing it at the same time. Upon resetting, we can view Bulbasaur, Charmander, Squirtle and Ivysaur as owned in the Pokédex, because the subroutine never got to reset those flags. I also show how it doesn't touch the seen flags, and how it can be used to disable the own entries if you back out in a normal way.
(Relevant code is here):
tcrf.net/Pok%C3%A9mon_Red_and_Blue#Starter%20Dex%20Entries
As documented in the Pokémon Red disassembly project and The Cutting Room Floor, when you view one of Professor Oak's three starters it temporarily marks Bulbasaur, Charmander and Squirtle as owned (as expected), before unsetting those flags. However, curiously Ivysaur is also marked as owned.
The player is also not expected to view the Pokédex list at this point, but if they did they would find those Pokémon as owned but not seen (unless they had already seen them). If the player views the Pokédex after the code unsets the own flags (i.e. backs out with B after viewing but not choosing the starter), any of the previous own entries before viewing the starters will also be disabled; so if you caught a Bulbasaur, Charmander, Squirtle or Ivysaur before viewing one of Professor Oak's Pokémon, this is a way of resetting all the entries again while retaining the seen flags.
In this video, I use arbitrary code execution to set up OAM DMA hijacking after the top-left border tile of the Pokédex entry is loaded into memory and partially save the game (using SaveSAVtoSRAM2; the function at pointer 780F in bank 0x1C), while freezing it at the same time. Upon resetting, we can view Bulbasaur, Charmander, Squirtle and Ivysaur as owned in the Pokédex, because the subroutine never got to reset those flags. I also show how it doesn't touch the seen flags, and how it can be used to disable the own entries if you back out in a normal way.
(Relevant code is here):
tcrf.net/Pok%C3%A9mon_Red_and_Blue#Starter%20Dex%20Entries
