Hello!

Thank you for the kind words. Contrary to Miguel you have noticed this is only what I achieved within my first 3 days of Rom Hacking. I have ZERO programming/coding knowledge and a few days ago I had ZERO knowledge on how to hack a Pokemon Rom. So yeah you all may say what you want and I know all is very raw still but I am quite happy with what I did so far.

As for the Aerodactyl Evolution, I tried it with GBA Pokemon Editor first and then with YAPE, as you can edit the evolutions in both, but with no success with any of the two.
It ALMOST worked as here is what happened. I added three new Pokemon in emtpy slots (the ???? after Celebi in the Pokemon list). The 3 evolutionary forms of Aerodactyl you see in my topmost post. Then, first in GBAPGE I edited Aerodactyl assigning it the 3 new Pokemon I added as Evolutions 1 - 3 (I think there are up to 5 slots for evolutions). Then I turned the evolution condition to "Item" and selected Waterstone, Firestone and Thunderstone for the respective evolutions. Also I added the proper sprites of the 3 Aerodactyl evolutions so they should be displayed properly in the game.

So as I said it ALMOST worked. Here is what happened in the game. The fat guy in Pallet Town gives you the three stones needed for the evolutions (I know enough about scripting to do that :D) and you can catch wild Aerodactyls in Pallet Town at levels 3 - 5. I did all that and went to the Items menu and tried to evolve Aerodactyl to Flarodactyl by selecting the Firestone, going "use" and selecting the Aerodactyl I had caught earlier. Then the evolution sequence starts and the player even says "Huh?" like one would expect. Then the game does not crash but the sequence aborts and you are back in the Pokemon menu screen. And Aerodactly is still Aerodactyl and the Fire Stone is still in your Items bag.

That is a detailed description of what I did and what happened in game.

Maybe it is helpful to someone willing to help me solve the problem.

I have an idea though. Do you guys think it would work if I would not add the 3 Aerodactyl Evolutions as new Pokemon (in the empty ??? slots after Celebi in the list) but would just replace existing Pokemon?? I shall try that but it should work the other way as well IMO...

Any help would be much appreciated.

Thanks,

Andi