Hacking GBA Flashcarts with GameCube Connectivity

[Eon-Rider]

I'm currently in the need of a GBA flashcart that I can use with my GameBoy Advance SP and my GameCube. I've done about 10 minutes of research and I've come to the conclusion that there were some flashcarts that had imperfect GameCube compatibility. This means some flashcarts work with certain games but not others.

The game I'm particularly interested is Pokemon Coloseum with the transferral of Celebi and Jirachi using the bonus discs.

I understand that GBA flashcarts are becoming rare because less people are playing GBA games so please help me by posting any experience you have and if you can recommend GBA flashcarts that work with this title.

Currently, I'm confident that the M3 Lite works well with the Pokemon games but it's a bit costly. I've always had my eye on the EZ Flash IV but I'm not confident it's compatible with Pokemon Coloseum. It seems the transfer of Pokemon always fails and even corrupts the save file.

 

[trance]

pokemon games use flash1m_v103 memory, most GBA flashcarts use varying types of sram.
this is why some gba games work on a flashcard (Mario Golf Advance Tour links properly to Toadstool Tour because advance tour uses sram). apparently, the efa-linker series has hardware-based support for flash saving (ie. it has a flash chip), the page for the efa brags about Super Mario Advance 4 (a game with a flash save) not needing to be patched for saving to sram.

in theory you either need to find the calls in the gc game for accessing the gba cart's memory and burn a modified copy of the game, or patch the calls in memory before the gba-side program transfers. otherwise, you'll just get scrambled pokemans from a save mismatch. i know you should be able to patch the celebi disc at least, because a friend who has the iso was able to find flash1m_v103 inside of it, you could try i suppose.

 

[how_do_i_do_that]

Games like that require that you load a single game to the flashcart in loaderless mode, regaurdless of how many games you can fit on it.

 

[trance]

yeah, a single-rom flash onto NOR is obviously required.
but the problem is that until there's a way to patch a gamecube disc or even a gba program contained inside, a flashcart with flash1m_v103 memory (if such a thing exists) is needed.
i've been working on something similar to this, but with changing Ruby and Sapphire support to suit my real Emerald cart so I can import from Pokemon Channel. there are a couple of things I know about how these pokemon links work, but not much really.

GPAU.iso, 0x4843AF98: "FLASH1M_V103"
GPAU.iso, 0x4843B0C0: "J E D F I S POKEMON RUBYAXV POKEMON SAPPAXP"
GPAU.iso, 0x4843B190: "SIIRTC_V001"

what i know is that there are three checks inside the code. that stuff above are excerpts from Channel, most likely only strings which could be modified.
1) checking the memory inside the gba cart, ie. looking for flash1m_v103 flash save memory. if there's sram, it could potentially mean bye-bye pokemans
2) checking the id/name of the cart. because i have a pal copy of channel, the intended jirachi is only for english and european games, essentially calling for all codes except J. with gba pokemon games, having the code xxxP on the cart's label is irrelevant, as it is xxxE inside the rom. game names are hard encoded in that iso as a string, but could be changed to emerald (POKEMON EMERBPE), leafgreen (POKEMON LEAFBPG) or firered (POKEMON FIREBPR). reordering the region codes may change which games could receive the pokemon (ie. J game receiving the jirachi).
3) check for the realtime clock. but, i think that this is only related to patching the berry program for Ruby and Sapphire. there's dialogue in the iso about the berry update not working or even not being needed, apparently this might apply in case of an update error (possible for forcing Emerald) or the update already installed (which the v1.1 r+s carts apparently have).

i haven't tested a lot of this stuff, let alone even attempting to patch (don't have a cube, and i've only just found out my wii has a backup-proof dvd drive). maybe some work in dolphin involving AR codes is required.

 

[how_do_i_do_that]

It is going to be VERY unlikely your going to be able to find or buy any flashcart that supports Flash in loaderless mode.

 

[trance]

@how_do_i_do_that: i'm only exploring options for those without a legit gba pokemon cart

i found the gba-side program on the Channel disc (pokechan.bin)
i don't know if there's any big way to simulate a multiboot program without the actual hardware itself (no gba just yet, and i haven't got the skill or resources to make the cable) or whether i can use a flashcard to do it between two gbas.

 

[damysteryman]

Interesting... I'll be happy to help out.

Got a modded Wii to play Pkmn Channel, and an EFA Simple flashcart. It's capable of playing pokemon games without any sram patches.

But I don't actually know what type of memory it has inside it though...

Tell me what you need done, and I'll test it. (I can't test origial carts, I've lost them...)