Delete Pokémon Diamond game data

When you arrive at the main menu (continue new game ...), press B, and you'll see an image of Palkia or Dialga. Then press UP + SELECT + B, and it will ask you "delete all saved data?". You choose yes or no according to your choice. That's it!! =) See you later and have a good game!

No, if you do that directly, you won't be able to save it. There's something else to do first.

No, that's exactly it... look, it shows me I need to do this:
press up on it + Select + control panel + B... I don't understand.

I believe all it takes is to start a new game.

I tried what you told me, it doesn't work. Someone had the game before me, it's Pokémon Pearl.

I did it but it doesn't work like that. I don't know if it needs to be done in a different way, but I've tried a lot...

again ??

You're welcome ;)

When you start the game, there is a big sign at the bottom that says new game, you go over it, press the A button and you start a new game.

press up + l + r + select + b

support then

You're welcome!!

https://eternia.fr/fr/site/index/

http://www.eternia-fr.net/pokemon_diamant_perle_index.html
http://www.eternia-fr.net/pokemon_rbj_index.html
http://www.eternia-fr.net/pokemon_rubis_saphir__index.html
http://www.eternia-fr.net/pokemon_rouge-feu_vert-feuille_index.html
http://www.eternia-fr.net/pokemon_or_argent_index.html
http://www.eternia-fr.net/pokemon__platine.html

http://www.eternia-fr.net/forum/index.php

More info here ^^

but to erase the game data it's UP+SELECT+B at the same time

As soon as you see your Dialga (when you turn it on after the video, press up and select at the same time and it will bring it up, there you go).