Just to confirm stuff, here’s an excerpt from TCRF about how to do this and what the fixed intro has: Although not completed yet and normally inaccessible, tidbits of a story mode do exist within the ROM. These can be accessed in the Gold debug ROM by changing 0x5585 from 0x8D to 0xB9. The data change will also cause serious issues with movement in some emulators, usually resulting in a crash.
Only the introduction up to the meet-up with the rival appear to be fully coded and playable.
Your rival is given a higher-level Pokémon when you first battle him after receiving your starters due to his party seemingly not being programmed yet, making progressing past this point difficult under normal circumstances.
Taken from this page:
https://tcrf.net/Proto:Pok%C3%A9mon_Gold_and_Silver#Story_ModeOnce again, this is nothing new and you can access this by editing the original ROM with a hex editor.
